MCQ 11 Mark
We get __________ current through rectifier without simple filter.
MCQ 21 Mark
On increasing the temperature, width of forbidden gap __________ .
MCQ 31 Mark
If the phase difference between two waves is $6 \pi$ radian, then corresponding path difference is __________ .
- ✓
$\lambda$
- B
$2 \lambda$
- C
$6 \lambda$
- D
$3 \lambda$
AnswerCorrect option: A. $\lambda$
View full question & answer→MCQ 41 Mark
Obtain the binding energy (in MeV ) of a nitrogen nucleus $\left({ }_7^{14} N\right)$, given $m(N)=\left({ }_7^{14} N\right)=14.00307 u$.
- ✓
$104.7$
- B
$10.47$
- C
$0.11236$
- D
$931.5$
AnswerCorrect option: A. $104.7$
View full question & answer→MCQ 51 Mark
Which of the following is true for the value of $\frac{N}{Z}$ for the nuclei of heavy element which are found stable ?
- A
$<1$
- B
$=1$
- ✓
$>1$ but $<2$
- D
$>2$
AnswerCorrect option: C. $>1$ but $<2$
View full question & answer→MCQ 61 Mark
The mass defeet is __________ for the stable nucleus.
MCQ 71 Mark
The atomic number of Helium is 4 and Sulphur $S$ is 32 . The radius of nucleus of sulphur is larger than that of Helium by __________ .
View full question & answer→MCQ 81 Mark
No. of protons and neutrons in hydrogen atom are respectively __________ .
MCQ 91 Mark
A difference of 2.3 eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom make a transition from the upper level to the lower level?
- A
$1.8 \times 10^{15} Hz$
- ✓
$5.6 \times 10^{14} Hz$
- C
$5.6 \times 10^{15} Hz$
- D
$1.8 \times 10^{-15} Hz$
AnswerCorrect option: B. $5.6 \times 10^{14} Hz$
View full question & answer→MCQ 101 Mark
The angular speed of the electron in the $n^{\text {th }}$ Bohr orbit of the hydrogen atom is proportional to __________ .
- A
$n$
- B
$n^3$
- C
$\frac{1}{n}$
- ✓
$\frac{1}{n^3}$
AnswerCorrect option: D. $\frac{1}{n^3}$
View full question & answer→MCQ 111 Mark
For which quantum number of the binding of electron is zero in hydrogen atom?
MCQ 121 Mark
According to classical physics, the kinetic energy K of an electron revolve in orbit of radius $r$ is __________ .
- ✓
$\frac{1}{8 \pi \varepsilon_0} \cdot \frac{Z e^2}{r}$
- B
$\frac{1}{4 \pi \varepsilon_0} \cdot \frac{Z e^2}{r}$
- C
$-\frac{1}{8 \pi \varepsilon_0} \cdot \frac{Z e^2}{r}$
- D
$-\frac{1}{4 \pi \varepsilon_0} \cdot \frac{Z e^2}{r}$
AnswerCorrect option: A. $\frac{1}{8 \pi \varepsilon_0} \cdot \frac{Z e^2}{r}$
View full question & answer→MCQ 131 Mark
If $E$ and $p$ are the energy and momentum of a photon respectively then on decreasing in the wavelength of photon.
- A
$p$ and $E$ both will decrease.
- ✓
$p$ and $E$ both will increase.
- C
$p$ will increase and $E$ will decrease.
- D
$p$ will decrease and $E$ will increase.
AnswerCorrect option: B. $p$ and $E$ both will increase.
View full question & answer→MCQ 141 Mark
When monochromatic source is kept at distance of $0.2$ m from photocell, cutoff voltage obtained is $0.6 V$ and saturation current is $18 mA$ . Now if source is kept at distance of $0.6 m$ __________ .
- A
stopping potential will be $0.2 V$
- ✓
stopping potential will be $0.6 V$
- C
saturation current will be $6 mA$
- D
saturation current will be $18 mA$
AnswerCorrect option: B. stopping potential will be $0.6 V$
View full question & answer→MCQ 151 Mark
Work function of metal is $\phi$ and wavelength of incident light is $\lambda$. Which condition should be followed for not emitting the photo-electrons ?
- ✓
$\lambda>\frac{h c}{\phi}$
- B
$\lambda=\frac{h c}{\phi}$
- C
$\lambda<\frac{h c}{\phi}$
- D
$\lambda \leq \frac{h c}{\phi}$
AnswerCorrect option: A. $\lambda>\frac{h c}{\phi}$
View full question & answer→MCQ 161 Mark
Scientist __________ performed experiment related to photo-electric effect.
MCQ 171 Mark
If diffraction pattern obtained by using violet light instead of patterns obtained by red light, then __________ .
- A
diffraction pattern will disappear.
- B
diffraction pattern will look unleashed.
- C
diffraction pattern remain constant.
- ✓
diffraction pattern will narrower.
AnswerCorrect option: D. diffraction pattern will narrower.
View full question & answer→MCQ 181 Mark
In Young's experiment if mica disc of thickness $t$ and refractive index $\mu$ is placed in the path of one ray coming out of slit, fringes will move __________ distance on the screen.
- A
$\frac{d}{D}(\mu-1) t$
- ✓
$\frac{D}{d}(\mu-1) t$
- C
$\frac{d}{(\mu-1) D}$
- D
$\frac{D}{d}(\mu-1)$
AnswerCorrect option: B. $\frac{D}{d}(\mu-1) t$
View full question & answer→MCQ 191 Mark
Velocity of light in rarer medium is $v_1$, it passes through denser medium with velocity $v_2$ incidents at ' $i$ ' angle and refracts by ' $r$ ' angle, then __________ .
View full question & answer→MCQ 201 Mark
Huygen's principle cannot explain __________ .
MCQ 211 Mark
A bird views a fish at 3 m depth in water, then Real depth of fish is __________ . (Refraction index of water is)
- ✓
- B
$\frac{9}{4} m$
- C
$\frac{4}{9} m$
- D
$\frac{3}{4} m$
View full question & answer→MCQ 221 Mark
If $f$ is focal length and $u$ is object distance for spherical mirror, then lateral magnification $m=$ __________ .
- A
$\frac{f}{u-f}$
- B
$\frac{f}{u+f}$
- ✓
$\frac{f}{f-u}$
- D
$\frac{f-u}{f}$
AnswerCorrect option: C. $\frac{f}{f-u}$
View full question & answer→MCQ 231 Mark
An object is placed at a distance of 25 cm on the axis of a concave mirror, having focal length 20 cm . Find the lateral magnification of an image.
MCQ 241 Mark
Electric field of one plane progressive electromagnetic wave is $E_Z=100 \cos (6$ $\left.\times 10^8 t+4 x\right) Vm ^{-1}$. Then refractive index of medium of propagation would be __________ .
View full question & answer→MCQ 251 Mark
If electric charge on capacitor formed by two plates of area $A$ is $Q$, then electric field between them __________ .
- ✓
$E =\frac{Q}{\varepsilon_0 A}$
- B
$E =\frac{Q}{2 \varepsilon_0 A}$
- C
$E =\frac{2 Q}{\varepsilon_0 A}$
- D
$\frac{\varepsilon_0 A}{Q}$
AnswerCorrect option: A. $E =\frac{Q}{\varepsilon_0 A}$
View full question & answer→MCQ 261 Mark
When 50 W bulb is connected with 220 V bulb, magnitude of rms current flowing in the bulb will __________ .
- A
$0.127 A$
- ✓
$0.227 A$
- C
$0.327 A$
- D
$0.427 A$
AnswerCorrect option: B. $0.227 A$
View full question & answer→MCQ 271 Mark
In an A.C. circuit, the capacitive reactance is defined as __________ .
- A
$Z _{ C }= j \omega C$
- B
$Z _{ C }=-\frac{1}{j \omega C}$
- C
$Z _{ C }=\frac{j}{\omega C}$
- ✓
$Z _{ C }=\frac{1}{j \omega C}$
AnswerCorrect option: D. $Z _{ C }=\frac{1}{j \omega C}$
View full question & answer→MCQ 281 Mark
When pendulum made of metal plate is allowed to oscillate between poles of magnet, amplitude of oscillation __________ .
MCQ 291 Mark
A coil has an area of $0.05 m^2$ and has 800 turns. After placing the coil in a magnetic field of strength $4 \times 10^{-5} Wb / m ^2$ perpendicular to the field the coil is rotated through $90^{\circ}$ in 0.1 s . The average emf induced is __________ .
- A
- ✓
$0.016 V$
- C
$0.01 V$
- D
$0.032 V$
AnswerCorrect option: B. $0.016 V$
View full question & answer→MCQ 301 Mark
A conducting rod of length $l$ and velocity $v$ moves in a magnetic field B . If $\rho$ Is the resistivity of the material of rod, then the induced current produced in the rod is __________ .
AnswerCorrect option: B. $\frac{B v A}{\rho}$
View full question & answer→MCQ 311 Mark
When a metallic rod falls freely, keeping its length horizontal and parallel to northsouth direction, emf induced across it is __________ .
MCQ 321 Mark
A 20 turn loop of radius 4 cm carries a current 3 A . If it placed in magnetic field of 0.5 T , the potential energy of dipole in most stable position is __________ J.
AnswerCorrect option: A. $-0.15$
View full question & answer→MCQ 331 Mark
Magnetic field at a point on axis is equal to magnetic field at point on equator of bar magnet ratio of these distance will be __________ .
- A
$2^{-3}: 1$
- B
$2^3: 1$
- ✓
$2^{-\frac{1}{3}}: 1$
- D
$2^{-\frac{1}{3}}: 1$
AnswerCorrect option: C. $2^{-\frac{1}{3}}: 1$
View full question & answer→MCQ 341 Mark
For a short magnet with magnetic dipole moment $\vec{m}$, its magnetic field at distance $d$ from its centre on its equator is __________ .
- ✓
$-\frac{\mu_0 m}{4 \pi d^3}$
- B
$\frac{\mu_0 m}{4 \pi d^2}$
- C
$\frac{\mu_0 m}{4 \pi d^3}$
- D
$\frac{\mu_0 m}{2 \pi d^3}$
AnswerCorrect option: A. $-\frac{\mu_0 m}{4 \pi d^3}$
View full question & answer→MCQ 351 Mark
At a distance of 10 cm from a long straight wire carrying current, the magnetic field is 0.04 T . At the distance of 40 cm , the magnetic field will be __________ .
- ✓
$001 T$
- B
$0.02 T$
- C
$ 0.08 T$
- D
$0.15 T$
AnswerCorrect option: A. $001 T$
View full question & answer→MCQ 361 Mark
The magnetic field at the centre of ring carrying electric current is __________ of area of the ring.
- ✓
inversely proportional to square root
- B
- C
- D
directly proportional to square root
AnswerCorrect option: A. inversely proportional to square root
View full question & answer→MCQ 371 Mark
Radius of circular path, followed by a charged particle is proportional to __________ .
MCQ 381 Mark
A small circular flexible loop of wire of radius $r$ carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be doubled if __________ .
AnswerCorrect option: C. $r$ is doubled
View full question & answer→MCQ 391 Mark
The direction of magnetic lines of forces close to a straight conductor carrying current will be __________ .
- A
Along the length of the conductor
- B
- ✓
Circular in a plane perpendicular to the conductor
- D
AnswerCorrect option: C. Circular in a plane perpendicular to the conductor
View full question & answer→MCQ 401 Mark
Unit of mobility is __________ .
- A
$m ^2 V^{-1} S^{-1}$
- B
$m ^2 \Omega^* C ^{-1}$
- C
$kg ^{-1} Cs$
- ✓
View full question & answer→MCQ 411 Mark
__________ is Ohm's law for good conductor.
- A
$V \propto R$
- ✓
$V \propto I$
- C
$I \propto R$
- D
$V \propto \frac{1}{R}$
AnswerCorrect option: B. $V \propto I$
View full question & answer→MCQ 421 Mark
Charge passing through the cross-section of a conductor is given by $Q = B ^{\prime}+$ $A ^{\prime} t^2$. What will be the current at time $t=10 s$ ?
- A
$5 A^{\prime}$
- B
$10 A^{\prime}$
- ✓
$20 A^{\prime}$
- D
$40 A^{\prime}$
AnswerCorrect option: C. $20 A^{\prime}$
View full question & answer→MCQ 431 Mark
Capacitance of spherical capacitor is $1 \mu F$, so its diameter $=$ __________ m.
$\left[\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 SI\right]$
- A
$1.8$
- B
- C
$1.8 \times 10^3$
- ✓
$1.8 \times 10^4$
AnswerCorrect option: D. $1.8 \times 10^4$
View full question & answer→MCQ 441 Mark
The charge $3.0 \times 10^{-5} C$ are placed on a metal sphere of radius 3.0 m , then the energy stored in it will be __________ .
- A
$\frac{3}{8 \pi} \varepsilon_0 \times 10^{10} J$
- ✓
$\frac{3}{8 \pi \varepsilon_0} \times 10^{-10} J$
- C
$\frac{3}{8 \varepsilon_0} \times 10^{-5} J$
- D
$\frac{8 \varepsilon_0}{3} \times 10^5 J$
AnswerCorrect option: B. $\frac{3}{8 \pi \varepsilon_0} \times 10^{-10} J$
View full question & answer→MCQ 451 Mark
Work required to give displacement of $x$ to a unit positive charge on an equipotential surface is __________ .
- ✓
- B
$x J$
- C
$\frac{1}{x} J$
- D
$q Ex J$
View full question & answer→MCQ 461 Mark
When a positive charge is brought to higher potential from lower potential, then potential energy __________ .
MCQ 471 Mark
Q is the charge on the surface of metal sphere having radius R . Then the electric potential at $\frac{ R }{2}$ distance inside the sphere is $l$ __________ .
- A
$V =4 \pi \varepsilon_0 R$
- B
$V =4 \pi \varepsilon_0(2 R )$
- C
$V=\frac{1}{4 \pi \varepsilon_0} \cdot \frac{Q}{2 R}$
- ✓
$V =\frac{1}{4 \pi \varepsilon_0} \cdot \frac{ Q }{ R }$
AnswerCorrect option: D. $V =\frac{1}{4 \pi \varepsilon_0} \cdot \frac{ Q }{ R }$
View full question & answer→MCQ 481 Mark
An infinite line charge produces a field of $9 \times 10^4 N / C$ at a distance of 2 cm . Calculate the linear charge density.
- A
$0.2 \mu Cm ^{-1}$
- B
$0.05 \mu Cm ^{-1}$
- ✓
$0.1 \mu Cm ^{-1}$
- D
$10 \mu Cm ^{-1}$
AnswerCorrect option: C. $0.1 \mu Cm ^{-1}$
View full question & answer→MCQ 491 Mark
Two copper spheres $A$ and $B$ have equal radii. If sphere $A$ has 100 electrons and sphere B has 400 protons then what will be the electric charge on each of them when they are brought in contact and separated ?
- A
$4.8 \times 10^{-17} C$
- ✓
$2.4 \times 10^{-17} C$
- C
$1.6 \times 10^{-17} C$
- D
$6.4 \times 10^{-17} C$
AnswerCorrect option: B. $2.4 \times 10^{-17} C$
View full question & answer→MCQ 501 Mark
__________ no. of electrons have charge equal to 1 columb.
- A
$6.25 \times 10^{19}$
- ✓
$6.25 \times 10^{18}$
- C
$6.25 \times 10^{20}$
- D
$1.6 \times 10^{19}$
AnswerCorrect option: B. $6.25 \times 10^{18}$
View full question & answer→