MCQ 11 Mark
The decay constant λ of a certain radioactive material is 0.2166 per day. The average life τ of the radioactive material is ______
AnswerThe decay constant λ of a certain radioactive material is 0.2166 per day. The average life τ of the radioactive material is 4.617 days.
View full question & answer→MCQ 21 Mark
In a single slit diffraction pattern, the first minima obtained with the red light of wavelength 6600 A.U. coincides with the first maxima f some other wavelength λ then is ______
AnswerIn a single slit diffraction pattern, the first minima obtained with the red light of wavelength 6600 A.U. coincides with the first maxima f some other wavelength λ then is 4400 A.U.
View full question & answer→MCQ 31 Mark
For which logic gate the following statement is true The output is low, if and only if all inputs are low ______ >
AnswerFor which logic gate the following statement is true The output is low, if and only if all inputs are low OR.
View full question & answer→MCQ 41 Mark
The speed of electron having de Broglie wavelength of $10^{-10} m$ is $\left(m_e=9.1 \times 10^{-31} kg , h =6.63 \times 10^{-34} J - s \right)$
- ✓
$7.28 \times 10^6 m / s$
- B
$4 \times 10^6 m / s$
- C
$8 \times 10^5 m / s$
- D
$5.25 \times 10^5 m / s$
AnswerCorrect option: A. $7.28 \times 10^6 m / s$
The speed of electron having de Broglie wavelength of $10^{-10} m$ is $7.28 \times 10^6 m / s$.
View full question & answer→MCQ 51 Mark
Four resistances 4 Ω, 8Ω, XΩ and 12Ω are connected in a series to form Wheatstone’s network. If the network is balanced, the value of X is ______.
AnswerFour resistances 4 Ω, 8Ω, XΩ, and 12Ω are connected in a series to form Wheatstone’s network. If the network is balanced, the value of X is 6.
View full question & answer→MCQ 61 Mark
A parallel plate capacitor with oil between the plates (dielectric constant of oil, $k =2$ ) has a capacitance $C$. If the oil is removed, then the capacitance of the capacitor becomes
- A
$2 C$
- B
$C \sqrt{2}$
- ✓
$\frac{c}{\sqrt{2}}$
- D
$\frac{c}{2}$
AnswerCorrect option: C. $\frac{c}{\sqrt{2}}$
A parallel plate capacitor with oil between the plates (dielectric constant of oil, $k=2$ ) has a capacitance $C$. If the oil is removed, then the capacitance of the capacitor becomes $\frac{c}{2}$.
View full question & answer→MCQ 71 Mark
The bending of a beam of light around corners of obstacle is called ______
AnswerThe bending of a beam of light around the corners of the obstacle is called Diffraction.
View full question & answer→MCQ 81 Mark
An organ pipe of length 0.4 m is open at both ends. The speed of sound in the air is 340 m/s. The fundamental frequency is ______
AnswerAn organ pipe of length 0.4 m is open at both ends. The speed of sound in the air is 340 m/s. The fundamental frequency is 425 Hz.
View full question & answer→MCQ 91 Mark
Two S.H.M.'s have zero phase difference and equal amplitudes A. The resultant amplitude on their composition will be
- ✓
$2 A$
- B
- C
$\sqrt{2} A$
- D
$\sqrt{2 A }$
AnswerTwo S.H.M.’s have zero phase difference and equal amplitudes A. The resultant amplitude on their composition will be 2 A.
View full question & answer→MCQ 101 Mark
Heating a gas in a constant volume container is an example of which process?
MCQ 111 Mark
Calculate the energy radiated in one minute by a blackbody of surface area $200 cm ^2$ at $127^{\circ} C (\sigma=5.7 x$ $10^{-8} J m ^{-2} s ^{-1} K ^{-4}$ )
- A
$1367.04 J$
- B
$1698.04 J$
- ✓
$1751.04 J$
- D
$1856.04 J$
AnswerCorrect option: C. $1751.04 J$
View full question & answer→MCQ 121 Mark
Two stones with radii 1:2 fall from a great height through the atmosphere. Their terminal velocities are in the ratio ______
- A
$2: 1$
- ✓
$1: 4$
- C
$4: 1$
- D
$1: 2$
AnswerCorrect option: B. $1: 4$
Two stones with radii 1:2 fall from a great height through the atmosphere. Their terminal velocities are in the ratio of 1:4
View full question & answer→MCQ 131 Mark
In a transistor amplifier, $IC = 5.5 mA , IE = 5.6 mA$. The current amplification factor $\beta$ is ______
AnswerIn a transistor amplifier, $I _{ C }=5.5 mA, I _{ E }=5.6 mA$. The current amplification factor $\beta$ is $5 5 .$.
View full question & answer→MCQ 141 Mark
In Hydrogen, the electron jumps from the fourth orbit to the second orbit. The wavenumber of the radiations emitted by an electron is_______
- A
$\frac{ R }{16}$
- ✓
$\frac{3 R }{16}$
- C
$\frac{5 R }{16}$
- D
$\frac{7 R }{16}$
AnswerCorrect option: B. $\frac{3 R }{16}$
In Hydrogen, the electron jumps from the fourth orbit to the second orbit. The wavenumber of the radiations emitted by an electron is $\frac{3 R }{16}$.
View full question & answer→MCQ 151 Mark
Planck's constant is $6.6 \times 10^{-34} Js$. The momentum of each photon is given radiation Is $3.3 \times 10^{-}$ ${ }^{29} kg / s$. The $\lambda$ of radiation is
- A
$2 \times 10^{10} m$
- B
$2 \times 10^7 m z$
- C
$2 \times 10^5 m$
- ✓
$2 \times 10^{-5} m$
AnswerCorrect option: D. $2 \times 10^{-5} m$
Planck's constant is $6.6 \times 10^{-34} Js$. The momentum of each photon is given radiation Is $3.3 \times 10^{-29} kg / s$. The $\lambda$ of radiation is $\underline{2 \times 10^{-5} m }$.
Explanation:
$\lambda=\frac{ h }{ p } $
$=\frac{6.6 \times 10^{-34}}{3.3 \times 10^{-29}} $
$=2 \times 10^{-5} m$
View full question & answer→MCQ 161 Mark
A coil of resistance $300 \Omega$ and inductance $1.0 H$ is connected across an alternating voltage of frequency $\frac{300}{2 \pi} Hz$, therefore phase difference between the voltage and current in the circuit is
- A
$180^{\circ}$
- ✓
$90^{\circ}$
- C
$45^{\circ}$
- D
$0^{\circ}$
AnswerCorrect option: B. $90^{\circ}$
A coil of resistance $300 \Omega$ and inductance $1.0 H$ is connected across an alternating voltage of frequency $\frac{300}{2 \pi} Hz$, therefore the phase difference between the voltage and current in the circuit is $4 5 ^{\circ}$.
View full question & answer→MCQ 171 Mark
A magnet is moved towards a coil (i) quickly (ii) slowly, then the induced e.m.f. is ______
- ✓
- B
- C
- D
larger or smaller depending upon the radius of the coil
AnswerA magnet is moved towards a coil (i) quickly (ii) slowly, then the induced e.m.f. is larger in case (i).
View full question & answer→MCQ 181 Mark
A magnetic material of susceptibility $3 \times 10-4$, and magnetic intensity is $4 \times 10-4 Am -1$. Then The magnetization in the units of Am-1 is..........
- ✓
$12 \times 10^8$
- B
$1.33 \times 10^8$
- C
$0.75 \times 10^{-8}$
- D
$14 \times 10^{-8}$
AnswerCorrect option: A. $12 \times 10^8$
A magnetic material of susceptibility $3 \times 10^{-4}$, and magnetic intensity is $4 \times 10^{-4} Am ^{-1}$. Then The magnetization in the units of $Am ^{-1}$ is $12 \times 10^8$.
View full question & answer→MCQ 191 Mark
A circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is ______
- A
$1.57 \times 10^{-3} Wb / m ^2$
- ✓
$8.0 \times 10^{-5} Wb / m ^2$
- C
$2.0 \times 10^{-3} Wb / m ^2$
- D
$3.14 \times 10^{-1} Wb / m ^2$
AnswerCorrect option: B. $8.0 \times 10^{-5} Wb / m ^2$
A circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is $8.0 \times 10^{-5} Wb / m ^2$
View full question & answer→MCQ 201 Mark
A string of length ℓ fixed at one end carries a mass m at the other. The string makes 2/π revolutions/sec around the vertical axis through the fixed end. The tension in the string is ______
AnswerA string of length ℓ fixed at one end carries a mass m at the other. The string makes 2/π revolutions/sec around the vertical axis through the fixed end. The tension in the string is 16 ml.
View full question & answer→MCQ 211 Mark
If the potential gradient of a wire decreases, then its length ______
AnswerIf the potential gradient of a wire decreases, then its length increases.
View full question & answer→MCQ 221 Mark
You are given a number of capacitors labelled as 8μF - 250V. Find the number of capacitors needed to get an arrangement equivalent to 16μF - 1000V.
MCQ 231 Mark
Which of the following cannot produce two coherent sources?
MCQ 241 Mark
The integral multiple of fundamental frequencies are ______
AnswerThe integral multiple of fundamental frequencies are harmonics.
View full question & answer→MCQ 251 Mark
When the displacement of a simple harmonic oscillator is half of its amplitude, its P.E. is 3 J. Its total energy is ______
AnswerWhen the displacement of a simple harmonic oscillator is half of its amplitude, its P.E. is 3 J. Its total energy is 12 J.
View full question & answer→MCQ 261 Mark
The second law of thermodynamics deals with the transfer of ______
AnswerThe second law of thermodynamics deals with the transfer of heat.
View full question & answer→MCQ 271 Mark
The molar specific heat of a gas at constant volume is 12307.69 J kg-1 K-1. If the ratio of the two specific heats is 1.65, calculate the difference between the two molar specific heats of gas.
- ✓
$7999 J kg ^{-1} K ^{-1}$
- B
$7245 J kg ^{-1} K ^{-1}$
- C
$6890 J kg ^{-1} K ^{-1}$
- D
$4067 J kg ^{-1} K ^{-1}$
AnswerCorrect option: A. $7999 J kg ^{-1} K ^{-1}$
$7999 J kg ^{-1} K ^{-1}$
View full question & answer→MCQ 281 Mark
The energy stored in a soap bubble of diameter $6$ cm and $T = 0.04 N/m$ is nearly
- ✓
$0.9 \times 10^{-3} J$
- B
$0.4 \times 10^{-3} J$
- C
$0.7 \times 10^{-3} J$
- D
$0.5 \times 10^{-3} J$
AnswerCorrect option: A. $0.9 \times 10^{-3} J$
The energy stored in a soap bubble of diameter $6 cm$ and $T=0.04$ $N / m$ is nearly $0 . 9 \times 10^{-3} J$
Explanation:
Increase in surface area of the sphere is given by:
$A =4 \pi r^2$
Here, $r$ is the radius of the sphere and $A$ is the increase in the surface area.
The bubble contains two surfaces. So multiply Equation (i) by $2$
$A=2 \times 4 \pi r^2$
Substitute the value of $r=3 cm$ to find the value of the area.
$A=2 \times 4 \pi \times\left(3 cm \times \frac{1 m }{100 cm }\right)^2$
$A=0.023 m ^2$
The formula for stored energy is:
$E = T \times A$
Here, $T$ is the surface tension.
Substitute the value of $T=0.04 N / m$ and $A=0.023 m ^2$ to find the stored energy.
$E=T \times A $
$E=0.04 N / m \times 0.023 m ^2$
$E=0.9 \times 10^{-3} J$
View full question & answer→MCQ 291 Mark
For a transistor $\beta=75$ and $IE =7.5 mA$. The value of $\alpha$ is.......
AnswerFor a transistor $\beta=75$ and $I _{ E }=7.5 mA$. The value of $\alpha$ is $0 . 9 8$.
View full question & answer→MCQ 301 Mark
The dimensions of Rydberg’s constant are ______
- A
$\left[M^0 L^1 T^0\right]$
- ✓
$\left[ M ^0 L ^{-1} T ^0\right]$
- C
$\left[M^0 L^1 T^1\right]$
- D
$\left[ M ^0 L ^{-1} T ^{-1}\right]$
AnswerCorrect option: B. $\left[ M ^0 L ^{-1} T ^0\right]$
The dimensions of Rydberg’s constant are $\left[M^0 L^{-1} T^0\right]$
View full question & answer→MCQ 311 Mark
Ultraviolet radiation of 6.2 eV falls on an aluminum surface (work function 4.2 eV). The kinetic energy in joules of the fastest electron emitted is ______
- A
$3.2 \times 10^{-21}$
- ✓
$3.2 \times 10^{-19}$
- C
$3.2 \times 10^{-1}$
- D
$3.2 \times 10^{-15}$
AnswerCorrect option: B. $3.2 \times 10^{-19}$
Ultraviolet radiation of 6.2 eV falls on an aluminum surface (work function 4.2 eV). The kinetic energy in joules of the fastest electron emitted is $3.2 \times 10^{-19}$
View full question & answer→MCQ 321 Mark
An electric bulb operates 10 V d.c. If this bulb is connected to an a.c. source and gives normal brightness, then the peak value of the source is ______
AnswerAn electric bulb operates 10 V d.c. If this bulb is connected to an a.c. source and gives normal brightness, then the peak value of the source is 14.14 V.
View full question & answer→MCQ 331 Mark
Two pure inductors each of self-inductance L are connected in series, the net inductance is ______
AnswerTwo pure inductors each of self-inductance L are connected in series, the net inductance is 2L.
View full question & answer→MCQ 341 Mark
What is the magnetization of a bar magnet having a length of $6 cm$ and the area of cross-section $5 cm ^2$ ?
- A
$1.2 \times 10^{-4} A / m$
- ✓
$3.3 \times 10^4 A / m$
- C
$1.25 \times 10^{-4} A / m$
- D
$3.3 \times 10^{-4} A / m$
AnswerCorrect option: B. $3.3 \times 10^4 A / m$
$3.3 \times 10^4 A / m$
Explanation:
$I =6 cm , \Delta=5 cm ^2, M =1 Am ^2$
$\text { magnetization }= $
$\frac{\text { Magnetic moment }}{\text { Volume }}=\frac{ Am ^2}{ m ^3}= Am ^{-1}$
$=\frac{1 Am ^2}{6 \times 5 cm ^3}=\frac{1 Am ^2}{30 \times 10^{-6} m ^3}=\frac{10^6}{30} Am ^{-1}$
$=\frac{1}{3} \times 10^5=0.33 \times 10^5=3.3 \times 10^4 Am ^{-1}$
View full question & answer→MCQ 351 Mark
The magnetic dipole moment of the current loop is independent of ______
- A
- B
- C
- ✓
the magnetic field in which it is lying
AnswerCorrect option: D. the magnetic field in which it is lying
The magnetic dipole moment of the current loop is independent of the magnetic field in which it is lying.
View full question & answer→MCQ 361 Mark
A cyclist riding a bicycle at a speed of $14 \sqrt{3} m / s$ takes a turn around a circular road of radius $20 \sqrt{3} m$ without skidding. Given $g =9.8$ $m / s ^2$, what is his inclination to the vertical
- A
$30^{\circ}$
- B
$45^{\circ}$
- ✓
$60^{\circ}$
- D
$90^{\circ}$
AnswerCorrect option: C. $60^{\circ}$
A cyclist riding a bicycle at a speed of $14 \sqrt{3} m / s$ takes a turn around a circular road of radius $20 \sqrt{3} m$ without skidding. Given $g =9.8$ $m / s ^2$, what is his inclination to the vertical $\underline{ 6 }{ }^{\circ}$
View full question & answer→MCQ 371 Mark
When the null point is obtained in the potentiometer, the current is drawn from the ______
- ✓
- B
- C
both main and cell battery
- D
neither main nor cell battery
AnswerWhen the null point is obtained in the potentiometer, the current is drawn from the main battery.
View full question & answer→MCQ 381 Mark
The work done in carrying a charge $Q$ once round a circle of radius $r$ with charge $q$ at the centre of the circle is
AnswerThe work done in carrying a charge Q once round a circle of radius r with charge q at the centre of the circle is Zero.
View full question & answer→MCQ 391 Mark
The path difference between two waves meeting at a point is (11/4)λ. The phase difference between the two waves is ______
AnswerThe path difference between two waves meeting at a point is (11/4)λ. The phase difference between the two waves is 11 π/2.
View full question & answer→MCQ 401 Mark
In the law of tension, the fundamental frequency of the vibrating string is, ______
- A
inversely proportional to the square root of tension
- B
directly proportional to the square of tension
- ✓
directly proportional to the square root of the tension
- D
inversely proportional to the density
AnswerCorrect option: C. directly proportional to the square root of the tension
In the law of tension, the fundamental frequency of the vibrating string is directly proportional to the square root of the tension.
View full question & answer→MCQ 411 Mark
The maximum speed of a particle executing S.H.M. is 10 m/s and maximum acceleration is 31.4 m/s2. Its periodic time is ______
AnswerThe maximum speed of a particle executing S.H.M. is 10 m/s and maximum acceleration is $31.4 m / s ^2$. Its periodic time is 2 s.
View full question & answer→MCQ 421 Mark
Choose the correct option. A gas in a closed container is heated with 10 J of energy, causing the lid of the container to rise 2m with 3N of force. What is the total change in energy of the system?
Answer4J Explanation:
Write the equation from the first law of thermodynamics.
ΔU = Q – W
Write the expression of work done.
W = F × Δx
W = (3N) × (2m)
W = 6J
Substitute 10J for Q and 6J for W to find a change in energy.
ΔU = 10J – 6J
ΔU = 4J
View full question & answer→MCQ 431 Mark
Calculate the value of λmax for radiation from a body having a surface temperature of 3000 K. (b = 2.897 x 10-3 m K)
MCQ 441 Mark
Two capillary tubes of radii 0.6 cm and 0.3 cm are dipped in the same liquid. The ratio of heights through which the liquid will rise in the tubes is ______
- A
$2: 1$
- ✓
$1: 2$
- C
$4: 1$
- D
$1: 4$
AnswerCorrect option: B. $1: 2$
Two capillary tubes of radii 0.6 cm and 0.3 cm are dipped in the same liquid. The ratio of heights through which the liquid will rise in the tubes is 1:2
View full question & answer→MCQ 451 Mark
In a common base configuration, the transistor has an emitter current of 10 mA and a collector current of 9.8 mA. The value of base current is ______
AnswerIn a common base configuration, the transistor has an emitter current of 10 mA and a collector current of 9.8 mA. The value of the base current is 0.2 mA.Explanation:
Let $I _{ e } b _{ e }$ emitter current $I _{ b } b _{ e }$ base current and $I _{ c } b _{ e }$ collector current.
$I_e=I_b+I_c$
$10 mA=I_b+9.8 mA$
$>I_b=0.2 mA .$
View full question & answer→MCQ 461 Mark
For the hydrogen atom, the minimum excitation energy ( of n =2) is ______For the hydrogen atom, the minimum excitation energy ( of n =2) is ______
AnswerFor the hydrogen atom, the minimum excitation energy ( of n =2) is 10.2 eV.
View full question & answer→MCQ 471 Mark
The work function of a metal is 4.2 Ev. Its threshold wavelength will be ______
AnswerThe work function of a metal is 4.2 Ev. Its threshold wavelength will be 2959 Å.
View full question & answer→MCQ 481 Mark
A parallel LC resonant circuit is used as ______
- A
a tunning circuit in a television receiver set.
- B
- C
- ✓
AnswerA parallel LC resonant circuit is used as a filter circuit.
View full question & answer→MCQ 491 Mark
In the expression e = –dΦ/dt, the -ve sign signifies ______
- A
The induced emf is produced only when magnetic flux decreases
- ✓
The induced emf opposes the change in the magnetic flux
- C
The induced emf is opposite to the direction of the flux.
- D
The induced emf is independent of change in magnetic flux.
AnswerCorrect option: B. The induced emf opposes the change in the magnetic flux
In the expression e = –dΦ/dt, the -ve sign signifies the induced emf opposes the change in the magnetic flux.
View full question & answer→MCQ 501 Mark
Relative permeability of iron 5500, then its magnetic susceptibility will be ______
- A
$5500 \times 10^7$
- B
- ✓
- D
$5500 \times 10^{-7}$
AnswerRelative permeability of iron 5500 , then its magnetic susceptibility will be $\underline{ 5 4 9 9 }$.
Explanation:
$
\chi_m=\left(\mu_r-1\right) \Rightarrow \chi_m=(5500-1)=5499
$
View full question & answer→MCQ 511 Mark
Which of the following is not a unit of magnetic induction?
MCQ 521 Mark
A $500$ kg car takes a round turn of the radius of $50m$ with a velocity of $36$ km/hr. The centripetal force is ______.
- A
$2500 N$
- B
$250 N$
- ✓
$1000 N$
- D
$1200 N$
AnswerCorrect option: C. $1000 N$
A $500$ kg car takes a round turn of the radius of $50$m with a velocity of $36$ km/hr. The centripetal force is $1000$N. Explanation:
Given: $m = 500 kg, R = 50 m >$
Velocity of the car $v=36 km / hr =36 \times \frac{5}{18}=10 m / s$
$\therefore$ Centripetal force $F =\frac{ mv ^2}{ R }$
$=\frac{500 \times 10^2}{50} $
$=1000 N$
View full question & answer→MCQ 531 Mark
The instrument which can measure terminal potential difference as well as electromotive force (emf) is ______
- A
Wheatstone’s meter bridge
- B
- ✓
- D
AnswerThe instrument which can measure terminal potential difference, as well as electromotive force (emf), is the potentiometer.
View full question & answer→MCQ 541 Mark
If an electron is brought towards another electron, the electric potential energy of the system ______
AnswerIf an electron is brought towards another electron, the electric potential energy of the system increases.
View full question & answer→MCQ 551 Mark
Young’s double-slit experiment is carried out using green, red and blue light, one colour at a time. The fringe widths recorded are WG, WR, and WB respectively then ______
AnswerYoung’s double-slit experiment is carried out using green, red and blue light, one colour at a time. The fringe widths recorded are WG, WR, and WB respectively then $W_R>W_G>W_B$
View full question & answer→MCQ 561 Mark
A set of tuning forks is arranged in ascending order of frequencies each tuning fork gives 8 beats/s with the preceding one. If the frequency of the first tuning fork is 120 Hz and the last fork is 200 Hz, then the number of tuning forks arranged will be, ______
AnswerA set of tuning forks is arranged in ascending order of frequencies each tuning fork gives 8 beats/s with the preceding one. If the frequency of the first tuning fork is 120 Hz and the last fork is 200 Hz, then the number of tuning forks arranged will be 11.
View full question & answer→MCQ 571 Mark
In a second’s pendulum, the mass of Bob is 50 g. If it is replaced by 100 g mass, then its period will be ______.
AnswerIn a second’s pendulum, the mass of Bob is 50 g. If it is replaced by 100 g mass, then its period will be 2 s.
View full question & answer→MCQ 581 Mark
For work done to be reversible, the process should be ______
AnswerFor work done to be reversible, the process should be adiabatic.
View full question & answer→MCQ 591 Mark
If the absolute temperature of a body is doubled, the power radiated will increase by a factor of ______
AnswerIf the absolute temperature of a body is doubled, the power radiated will increase by a factor of 16.
View full question & answer→MCQ 601 Mark
Unit of the coefficient of viscosity is ______
AnswerCorrect option: D. $Ns/m^2$
Unit of the coefficient of viscosity is $Ns / m ^2$
View full question & answer→MCQ 611 Mark
The Boolean expression for Exclusive OR gate (X-OR gate) is
- A
$A + B$
- ✓
$A \oplus B$
- C
$\overline{ A + B }$
- D
AnswerCorrect option: B. $A \oplus B$
The Boolean expression for Exclusive OR gate (X-OR gate) is
A ⊕ B. Explanation:
The logic or Boolean expression given for a logic OR gate is that of logical addition which is denoted by a standard plus sign. The symbol used to describe the Boolean expression for an Exclusive-OR function is a plus sign, (+) within a circle (Ο).
View full question & answer→MCQ 621 Mark
The ionization energy of Hydrogen atom in its ground state is ______
AnswerThe ionization energy of the Hydrogen atom in its ground state is 13.6 eV.
View full question & answer→MCQ 631 Mark
According to De-Broglie, the waves are associated with ______
- A
moving neutral particles only.
- B
moving charged particle only.
- C
- ✓
all moving matter particles
AnswerCorrect option: D. all moving matter particles
According to De-Broglie, the waves are associated with all moving matter particles.
View full question & answer→MCQ 641 Mark
If AC voltage is applied to a pure capacitor, then the voltage across the capacitor ______
- A
Leads the current by phase angle π rad.
- B
Leads the current by phase π/2 rad.
- C
Lags the current by phase angle π rad.
- ✓
Lags the current by phase angle π/2 rad.
AnswerCorrect option: D. Lags the current by phase angle π/2 rad.
If AC voltage is applied to a pure capacitor, then the voltage across the capacitor Lags the current by phase angle π/2 rad.
View full question & answer→MCQ 651 Mark
The energy stored in a 50 mH inductor carrying a current of 4 A is ______
AnswerThe energy stored in a 50 mH inductor carrying a current of 4 A is 0.4 J.
View full question & answer→MCQ 661 Mark
If $m _0$ and $L$ denote the orbital angular moment and the angular momentum of the electron due to its orbital motion, then the gyromagnetic ratio is given by
- A
$\frac{L}{m_0}$
- ✓
$\frac{m_0}{L}$
- C
$Lm _0$
- D
$\sqrt{\frac{m_0}{L}}$
AnswerCorrect option: B. $\frac{m_0}{L}$
If $m_0$ and $L$ denote the orbital angular moment and the angular momentum of the electron due to its orbital motion, then the gyromagnetic ratio is given by $\frac{m_0}{L}$.
View full question & answer→MCQ 671 Mark
The force between two parallel current-carrying conductors is F. If the current in each conductor is doubled, then the force between them becomes ______
AnswerThe force between two parallel current-carrying conductors is F. If the current in each conductor is doubled, then the force between them becomes 4F.
View full question & answer→MCQ 681 Mark
The moment of inertia of a circular loop of radius R, at a distance of R/2 around a rotating axis parallel to horizontal diameter of the loop is ______
- A
$1 / 2$ MR2 $
- ✓
$3 / 4 M R^2$
- C
- D
AnswerCorrect option: B. $3 / 4 M R^2$
The moment of inertia of a circular loop of radius R, at a distance of R/2 around a rotating axis parallel to the horizontal diameter of the loop is $3 / 4 M R^2$
View full question & answer→MCQ 691 Mark
The SI unit of the potential gradient is ______
AnswerThe SI unit of the potential gradient is V/m.
View full question & answer→MCQ 701 Mark
A dipole is placed in a uniform electric field, its potential energy will be minimum when the angle between its axis and field is
- A
$2 \pi$
- B
$\pi$
- C
$\frac{\pi}{2}$
- ✓
AnswerA dipole is placed in a uniform electric field, its potential energy will be minimum when the angle between its axis and field is Zero.
View full question & answer→MCQ 711 Mark
Light follows wave nature because ______
- A
Light rays travel in a straight line
- B
Light exhibits the phenomenon of reflection and refraction
- ✓
Light exhibits the phenomenon of interference
- D
Light causes the phenomenon of the photoelectric effect
AnswerCorrect option: C. Light exhibits the phenomenon of interference
Light follows wave nature because Light exhibits the phenomenon of interference.
View full question & answer→MCQ 721 Mark
A man standing unsymmetrical position between two mountains and fires a gun. He hears the first echo after 1.5 s and the second echo after 2.5 s. If the speed of sound in air is 340 m/s, then the distance between the mountains will be ______
AnswerA man standing unsymmetrical position between two mountains and fires a gun. He hears the first echo after 1.5 s and the second echo after 2.5 s. If the speed of sound in the air is 340 m/s, then the distance between the mountains will be 680 m.
View full question & answer→MCQ 731 Mark
Acceleration of a particle executing S.H.M. at its mean position.
AnswerThe acceleration of a particle executing S.H.M. at its mean position is zero.
View full question & answer→MCQ 741 Mark
Two systems at the same temperature are said to be in ______
AnswerTwo systems at the same temperature are said to be in thermal equilibrium.
View full question & answer→MCQ 751 Mark
The power radiated by a perfect blackbody depends only on its ______
AnswerThe power radiated by a perfect blackbody depends only on its temperature.
View full question & answer→MCQ 761 Mark
The surface tension of a liquid at critical temperature is ______
- A
- ✓
- C
Same as any other temperature
- D
AnswerThe surface tension of a liquid at critical temperature is Zero.
View full question & answer→MCQ 771 Mark
Choose the correct option. Solar cell operates on the principle of ______.
AnswerSolar cell operates on the principle of
photovoltaic action.
Explanation:
In photovoltaic action, generation of voltage takes place due to bombardment of the light photons.
View full question & answer→MCQ 781 Mark
According to Bohr's second postulate, the angular momentum of the electron is the integral multiple of $\frac{h}{2 \pi}$.The S.I unit of Plank constant $h$ is the same as________
AnswerAccording to Bohr's second postulate, the angular momentum of the electron is the integral multiple of $\frac{h}{2 \pi}$. The S.I unit of Plank constant $h$ is the same as angular momentum.
View full question & answer→MCQ 791 Mark
The maximum kinetic energy of the photoelectrons depends only on ______
AnswerThe maximum kinetic energy of the photoelectrons depends only on frequency.
View full question & answer→MCQ 801 Mark
A series LCR resonant circuit is used as ______
- A
A potential divider circuit.
- B
- C
A source of displacement current
- ✓
A tunning circuit in a television receiver set.
AnswerCorrect option: D. A tunning circuit in a television receiver set.
A series LCR resonant circuit is used as a tunning circuit in a television receiver set.
View full question & answer→MCQ 811 Mark
The role of inductance is equivalent to ______
AnswerThe role of inductance is equivalent to inertia.
View full question & answer→MCQ 821 Mark
If an electron of charge $(-e)$ and mass $m_e$ revolves around the nucleus of an atom having an orbital magnetic moment $m_0$, then the angular momentum of the electron is
- A
$L =\frac{m_0 e}{2 m_e}$
- B
$L =\frac{e}{2 m_0 m_e}$
- ✓
$L =\frac{2 m_0 m_e}{e}$
- D
$L =\frac{2 e}{m_0 m_e}$
AnswerCorrect option: C. $L =\frac{2 m_0 m_e}{e}$
If an electron of charge $(-e)$ and mass $m_e$ revolves around the nucleus of an atom having an orbital magnetic moment $m _0$, then the angular momentum of the electron is $L =\underline{\frac{2 m_0 m_e}{e}}$
View full question & answer→MCQ 831 Mark
A strong magnetic field is applied to a stationary electron. Then the electron ______
- A
moves in the direction of the field
- ✓
- C
moves perpendicular to the direction of the field
- D
moves opposite to the direction of the field
AnswerA strong magnetic field is applied to a stationary electron. Then the electron remained stationary.
View full question & answer→MCQ 841 Mark
A stone is tied to one end of a string. Holding the other end, the string is whirled in a horizontal plane with progressively increasing speed. It breaks at some speed because ______
- A
The gravitational forces of the earth are greater than the tension in the string
- ✓
The required centripetal force is greater than the tension sustained by the string
- C
The required centripetal force is lesser than the tension in the string
- D
The centripetal force is greater than the weight of the stone
AnswerCorrect option: B. The required centripetal force is greater than the tension sustained by the string
A stone is tied to one end of a string. Holding the other end, the string is whirled in a horizontal plane with progressively increasing speed. It breaks at some speed because The required centripetal force is greater than the tension sustained by the string.
View full question & answer→MCQ 851 Mark
When unknown resistance is determined by meter bridge, the error due to contact resistance is minimised by ______
- A
connecting both the resistances only in one gap
- ✓
interchanging the position of known and unknown resistances
- C
- D
obtaining the null point near the ends of the wire
AnswerCorrect option: B. interchanging the position of known and unknown resistances
When unknown resistance is determined by meter bridge, the error due to contact resistance is minimised by interchanging the position of known and unknown resistances.
View full question & answer→MCQ 861 Mark
Capacitance (in F) of a spherical conductor of radius 1m is ______
- ✓
$1.1 \times 10^{-10}$
- B
$9 \times 10^{-9}$
- C
$10^{-6}$
- D
$10^{-3}$
AnswerCorrect option: A. $1.1 \times 10^{-10}$
Capacitance (in F) of a spherical conductor of radius 1m is $1.1 \times 10^{-10}$.
View full question & answer→MCQ 871 Mark
Light of wavelength 5000 A.U. falls on a plane reflecting surface. The frequency of reflected light is ______
AnswerCorrect option: A. $6 \times 10^{14} Hz$
Light of wavelength 5000 A.U. falls on a plane reflecting surface. The frequency of reflected light is $6 \times 10^{14} Hz$
View full question & answer→MCQ 881 Mark
The equation of a simple harmonic progressive wave is given by, $y=$ $5 \cos \pi\left[200 t-\frac{x}{150}\right]$, where $x$ and $y$ are in $cm$ and ' $t$ ' is in second. Then the velocity of the wave is
- A
$2 m / s$
- B
$150 m / s$
- C
$200 m / s$
- ✓
$300 m / s$
AnswerCorrect option: D. $300 m / s$
The equation of a simple harmonic progressive wave is given by, $y =$ $5 \cos \pi\left[200 t-\frac{x}{150}\right]$, where $x$ and $y$ are in $cm$ and ' $t$ ' is in second.
Then the velocity of the wave is $300 m / s$.
Explanation:
$y=5 \cos \left[200 \pi t-\frac{\pi}{150} x\right]$
$y=A \cos (\omega t-K x) $
$A=5 cm $
$\omega=200 \pi $
$2 \pi f=200 \pi=100 Hz $
$K=\frac{\pi}{150}=\frac{2 \pi}{\lambda} $
$\lambda=300 cm $
$V=f \lambda=100 \times 300 \times 10^{-2}=300 m / s$
View full question & answer→MCQ 891 Mark
A particle is performing simple harmonic motion with amplitude A and angular velocity ω. The ratio of maximum velocity to maximum acceleration is ______.
AnswerA particle is performing simple harmonic motion with amplitude A and angular velocity ω. The ratio of maximum velocity to maximum acceleration is 1/ω.
View full question & answer→MCQ 901 Mark
Which of the following system freely allows the exchange of energy and matter with its environment?
MCQ 911 Mark
The number of degrees of freedom, for the vibrational motion of a polyatomic molecule, depends on the ______
- ✓
geometric structure of the molecule
- B
- C
the energy of the molecule
- D
the absolute temperature of the molecule
AnswerCorrect option: A. geometric structure of the molecule
The number of degrees of freedom, for the vibrational motion of a polyatomic molecule, depends on the geometric structure of the molecule.
View full question & answer→MCQ 921 Mark
The water droplets are spherical in free fall due to ______
- A
- B
intermolecular attraction
- ✓
- D
AnswerThe water droplets are spherical in free fall due to Surface tension.
View full question & answer→MCQ 931 Mark
A LED emits visible white light when its ______
- A
junction is reversed-biased.
- B
- ✓
holes and electrons recombine.
- D
AnswerCorrect option: C. holes and electrons recombine.
A LED emits visible white light when its
holes and electrons recombine. Explanation:
LED is a semi-conductor source of light which emits light when current flows through it. When electrons in semiconductors recombine with electron holes, releasing energy, in the form of photons.
View full question & answer→MCQ 941 Mark
The radii of Bohr orbit are directly proportional to ______
- A
- ✓
Square of principal quantum number
- C
Cube of principal quantum number
- D
Independent of principal quantum number
AnswerCorrect option: B. Square of principal quantum number
The radii of Bohr orbit are directly proportional to the Square of principal quantum number.
View full question & answer→MCQ 951 Mark
As the intensity of incident light increases ______
- ✓
photoelectric current increases
- B
photoelectric current decreases.
- C
the kinetic energy of emitted photoelectrons increases
- D
the kinetic energy of emitted photoelectrons decreases.
AnswerCorrect option: A. photoelectric current increases
As the intensity of incident light increases photoelectric current increases.
View full question & answer→MCQ 961 Mark
In a series LCR circuit at resonance, the applied emf and current are - ______
- A
- B
Differ in phase by π/4 radian.
- C
Differ in phase by π/2 radian.
- ✓
AnswerIn a series LCR circuit at resonance, the applied emf and current are - In phase.
View full question & answer→MCQ 971 Mark
An ideal transformer has 100 turns in the primary and 250 turns in the secondary. The peak value of the AC is $28 V$. The rms secondary voltage is nearest to
- A
$100 V$
- B
$70 V$
- ✓
$50 V$
- D
$40 V$
AnswerCorrect option: C. $50 V$
An ideal transformer has 100 turns in the primary and 250 turns in the secondary. The peak value of the AC is 28 V. The rms secondary voltage is nearest to 50 V.
View full question & answer→MCQ 981 Mark
The relation between relative permeability and magnetic susceptibility is given by
- A
$\chi=\mu_r+1$
- B
$\chi=-\mu_r-1$
- C
$\mu_r=1-\chi$
- ✓
$\mu_r=1+\chi$
AnswerCorrect option: D. $\mu_r=1+\chi$
The relation between relative permeability and magnetic susceptibility is given by $\mu_r=1+\chi$.
View full question & answer→MCQ 991 Mark
A conductor has three segments; two straights of length $L$ and a semicircular with radius $R$. It carries a current I What is the magnetic field $B$ at point $P$ ?
AnswerCorrect option: C. $\frac{\mu_0 I}{4 R}$
$\frac{\mu_0 I}{4 R}$
View full question & answer→MCQ 1001 Mark
The angular momentum of a system of particles is conserved ______
- A
When no external force acts upon the system
- ✓
When no external torque acts upon the system
- C
When no external impulse acts upon the system
- D
When the axis of rotation remains the same
AnswerCorrect option: B. When no external torque acts upon the system
The angular momentum of a system of particles is conserved When no external torque acts upon the system.
View full question & answer→MCQ 1011 Mark
Kirchhoff’s second law (voltage law) is based on ______
AnswerKirchhoff’s second law (voltage law) is based on the conservation of energy.
View full question & answer→MCQ 1021 Mark
A metal foil of negligible thickness is introduced between two plates of a capacitor at the centre. The capacitance of the capacitor will be ______
AnswerA metal foil of negligible thickness is introduced between two plates of a capacitor at the centre. The capacitance of the capacitor will be the Same.
View full question & answer→MCQ 1031 Mark
When light travels from an optically rarer medium to an optically denser medium, the speed decreases because of change in ______
AnswerWhen light travels from an optically rarer medium to an optically denser medium, the speed decreases because of the change in Wavelength.
View full question & answer→MCQ 1041 Mark
A standing wave is produced on a string fixed at one end with the other end free. The length of the string ______
- A
must be an odd integral multiple of λ
- B
must be an odd integral multiple of λ/2
- ✓
must be an odd integral multiple of λ/4
- D
must be an even integer multiple of λ
AnswerCorrect option: C. must be an odd integral multiple of λ/4
A standing wave is produced on a string fixed at one end with the other end free. The length of the string must be an odd integral multiple of λ/4.
View full question & answer→MCQ 1051 Mark
A particle is moving in a circle with uniform speed. Its motion is ______
- A
Periodic and simple harmonic
- B
- ✓
Periodic but not simple harmonic
- D
Non-periodic but simple harmonic
AnswerCorrect option: C. Periodic but not simple harmonic
A particle is moving in a circle with uniform speed. Its motion is Periodic but not simple harmonic.
View full question & answer→MCQ 1061 Mark
Which of the following is correct, when the energy is transferred to a system from its environment?
- ✓
- B
- C
- D
the system does not exchange energy
View full question & answer→MCQ 1071 Mark
The average energy per molecule is proportional to ______
- A
- B
- ✓
the absolute temperature of the gas
- D
AnswerCorrect option: C. the absolute temperature of the gas
The average energy per molecule is proportional to the absolute temperature of the gas.
View full question & answer→MCQ 1081 Mark
Insect moves over the surface of water because of ______
AnswerInsect moves over the surface of the water because of Surface tension.
View full question & answer→MCQ 1091 Mark
In a Bipolar junction transistor, the largest current flows through ______
AnswerIn a Bipolar junction transistor, the largest current flows through
in the emitter. Explanation:
Emitter supplies charge carriers. It is highly cloped so that it can inject a large no. of charge carriers into the base.
View full question & answer→MCQ 1101 Mark
When an electron jumps from a higher energy orbit to a lower energy orbit, the difference in the energies in the two orbits is radiated as quantum (photon) of
AnswerCorrect option: C. $E =\frac{ hc }{\lambda}$
When an electron jumps from a higher energy orbit to a lower energy orbit, the difference in the energies in the two orbits is radiated as quantum (photon) of $E =\frac{ hc }{\lambda}$.
View full question & answer→MCQ 1111 Mark
The electrons are emitted in the photoelectric effect from a metal surface.
- ✓
only if the frequency of radiation is above a certain threshold value.
- B
only if the temperature of the surface is high.
- C
at the that is independent of the nature of metal.
- D
with a maximum velocity proportional to the frequency of incident radiation
AnswerCorrect option: A. only if the frequency of radiation is above a certain threshold value.
The electrons are emitted in the photoelectric effect from a metal surface only if the frequency of radiation is above a certain threshold value.
View full question & answer→MCQ 1121 Mark
An electric current in an LC – circuit at resonance is called - ______
AnswerAn electric current in an LC – circuit at resonance is called - The wattless current.
View full question & answer→MCQ 1131 Mark
In which of the following devices, the eddy current is not used ______
- A
- B
- ✓
- D
Magnetic breaking in train
AnswerIn which of the following devices, the eddy current is not used Electric heater.
View full question & answer→MCQ 1141 Mark
The magnetic susceptibility is given by
AnswerCorrect option: D. $\chi=\frac{M}{H}$
The magnetic susceptibility is given by $x =\frac{M}{H}$.
View full question & answer→MCQ 1151 Mark
According to the right-hand rule, the direction of magnetic induction if the current is directed in an anticlockwise direction is ______
- A
perpendicular and inwards
- ✓
perpendicular and outwards
- C
- D
opposite to that of current
AnswerCorrect option: B. perpendicular and outwards
According to the right-hand rule, the direction of magnetic induction if the current is directed in an anticlockwise direction is perpendicular and outwards.
View full question & answer→MCQ 1161 Mark
A diver in a swimming pool bends his head before diving. It ______
- A
Increases his linear velocity
- ✓
Decreases his angular velocity
- C
Increases his moment of inertia
- D
Decreases his moment of inertia
AnswerCorrect option: B. Decreases his angular velocity
A diver in a swimming pool bends his head before diving. It Decreases his moment of inertia.
View full question & answer→MCQ 1171 Mark
The ratio of areas of the circular orbit of an electron in the ground state to that of the first excited state of an electron in a hydrogen atom is ______
- A
$16: 1$
- B
$4: 1$
- C
$1: 4$
- ✓
$1: 16$
AnswerCorrect option: D. $1: 16$
The ratio of areas of the circular orbit of an electron in the ground state to that of the first excited state of an electron in a hydrogen atom is 1 : 16.
View full question & answer→