MCQ 11 Mark
Width of a slit is a. The focal length of the lens kept just along with the slit is $f$. The light of wavelength $\lambda$ is made normally incident on the slit. The size of the central maximum on the screen is __________ .
- A
$\frac{a}{f \lambda}$
- B
$\frac{f a}{\lambda}$
- C
$\frac{\lambda a}{f}$
- ✓
$\frac{f \lambda}{a}$
AnswerCorrect option: D. $\frac{f \lambda}{a}$
View full question & answer→MCQ 21 Mark
Which one of the following sentence is false?
- A
Interference fringes are of equal thickness
- B
The central diffraction fringe is of maximum intensity
- C
All bright interference fringes are of equal intensities
- ✓
Diffraction fringes are of equal thickness
AnswerCorrect option: D. Diffraction fringes are of equal thickness
View full question & answer→MCQ 31 Mark
Unpolarised light is incident on a plane glass surface. For an angle of incidence __________ the reflected and refracted rays are perpendicular to each other?
Refractive index of glass $=1.5$.
- ✓
$37^{\circ}$
- B
$57^{\circ}$
- C
$47^{\circ}$
- D
$67^{\circ}$
AnswerCorrect option: A. $37^{\circ}$
View full question & answer→MCQ 41 Mark
The number of interference fringes occurring in the broad diffraction peak depends on the ratio __________ .
Where $d =$ distance between two slits
$a=$ width of slit
- ✓
$\frac{d}{a}$
- B
$\frac{d^2}{a}$
- C
$\frac{a}{d}$
- D
$\frac{a^2}{d}$
AnswerCorrect option: A. $\frac{d}{a}$
View full question & answer→MCQ 51 Mark
Object is placed 60 cm away from convex mirror. If magnification is 0.5 , image distance $=$ __________ .
View full question & answer→MCQ 61 Mark
An object is placed at 15 cm in front of a concave mirror of radius of curvature 20 cm . The image distance would be __________ cm .
MCQ 71 Mark
If a ray of light is incident on a plane mirror at an angle of $30^{\circ}$, then deviation produced by a plane mirror is __________ .
- A
$30^{\circ}$
- B
$60^{\circ}$
- C
$90^{\circ}$
- ✓
$120^{\circ}$
AnswerCorrect option: D. $120^{\circ}$
View full question & answer→MCQ 81 Mark
The focal length of objective lens and eyepiece is $f_0 $ and $f_e$ respectively. Magnifying power of the telescope $=$ __________ .
- A
$f_0 + f_e$
- ✓
$\frac{f_o}{f_e}$
- C
$f_0-f_e$
- D
$\frac{f_e}{f_o}$
AnswerCorrect option: B. $\frac{f_o}{f_e}$
View full question & answer→MCQ 91 Mark
A magician during a show makes a glass lens with refractive index $n = 1.5$ disappear in a trough of liquid. The refractive index of liquid $=$ __________ .
- ✓
$1.5$
- B
$0.75$
- C
$3.0$
- D
$0.15$
View full question & answer→MCQ 101 Mark
The refractive index of medium-3 with respect to medium-2 $n_{32}=$ __________ .
- ✓
$n_{31} \times n_{12}$
- B
$\frac{n_{12}}{n_{31}}$
- C
$\frac{n_{31}}{n_{12}}$
- D
$n_{13} \times n_{21}$
AnswerCorrect option: A. $n_{31} \times n_{12}$
View full question & answer→MCQ 111 Mark
Which one of the following electromagne wave is of minimum wavelength?
MCQ 121 Mark
A light of an energy $6.48 \times 10^5 J$ is incident normally on nonreflecting surface The momentum imparted on the surface is _________ N-s.
- A
$1.26 \times 10^{-3}$
- B
$21.6 \times 10^{-3}$
- C
$6.26 \times 10^{-3}$
- ✓
$2.16 \times 10^{-3}$
AnswerCorrect option: D. $2.16 \times 10^{-3}$
View full question & answer→MCQ 131 Mark
___________ current is obtained due to change in the electric field.
MCQ 141 Mark
An inductive reactance of an inductor is __________ .
- A
$\frac{1}{\omega L}$
- B
$\frac{1}{\omega C}$
- C
$\omega C$
- ✓
$\omega L$
AnswerCorrect option: D. $\omega L$
View full question & answer→MCQ 151 Mark
The power factor at the time of resonance is __________ .
MCQ 161 Mark
If $P_o$ is an output power and $P_i$ is an input power of a real step-up transfors then,
- A
$P_0=P_i$
- ✓
$P _{ o }< P _{ i }$
- C
$P_0>P_i$
- D
$P_0=\sqrt{2} P_1$
AnswerCorrect option: B. $P _{ o }< P _{ i }$
View full question & answer→MCQ 171 Mark
In DC circuit inductive reactance of inductance is __________ .
MCQ 181 Mark
Faraday's law gives __________ of induced emf.
- ✓
- B
- C
both magnitude and direction
- D
View full question & answer→MCQ 191 Mark
Current in a circuit falls from 5 A to 0 A in 0.1 s . If an average emf of 2 Wr induced, the self-inductance of the circuit would be ___________ H.
MCQ 201 Mark
A conducting coil having number of turns N and cross section area A is kept in such a way that its plane remains perpendicular to the uniform magnetic field B. Now, if the number of turns of the coil is made double then the magnetic flux linked with coil = __________ .
- A
- B
$N ^2 BA$
- C
$\frac{ NBA }{2}$
- ✓
View full question & answer→MCQ 211 Mark
A bar magnet is of length (size) $l$. The ratio of its equatorial field and axial field for the same distance $r$ (where $r >> l$) is __________ .
View full question & answer→MCQ 221 Mark
A short bar magnet placed with its axis at $30^{\circ}$ with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to $4.5 \times 10^{-2} J$. The magnitude of magnetic moment of the magnet is __________ $JT^{-1}$
- ✓
$0.36$
- B
$0.72$
- C
$0.18$
- D
$0.54$
AnswerCorrect option: A. $0.36$
View full question & answer→MCQ 231 Mark
The force acting on a north pole of magnet of pole strength 3200 Am and 10 cm away from the south pole of a point bar magnet of pole strength 40 Am is __________ N .
- A
$-1.28$
- ✓
$1.28$
- C
$1.28 \times 10^{-7}$
- D
$1.28 \times 10^7$
AnswerCorrect option: B. $1.28$
View full question & answer→MCQ 241 Mark
A solenoid of length 0.5 m has a radius of 1 cm and is made up of 1000 turns. It carries a current of 5 A . The magnitude of the magnetic field inside the solenoid is ________ T.
- A
$\pi \times 10^{-3}$
- B
$3 \pi \times 10^{-3}$
- C
$2 \pi \times 10^{-3}$
- ✓
$4 \pi \times 10^{-3}$
AnswerCorrect option: D. $4 \pi \times 10^{-3}$
View full question & answer→MCQ 251 Mark
Charge particles with the speed _________ can pass undeflected through the region of crossed electric field (E) and magnetic field (B) that serve as a velocity selector.
AnswerCorrect option: B. $\frac{E}{B}$
View full question & answer→MCQ 261 Mark
A particle having charge $q$ moving with velocity of $2 m / s$ in uniform magnetic field $\overrightarrow{ B }=(\vec{i}+2 \vec{j}+3 \vec{k}) T$. Particle moves in X-direction. Force acting on it will be in __________ .
- ✓
$ZY plane$
- B
$- Y-axis$
- C
$+ Z-axis$
- D
$- Z-axis$
AnswerCorrect option: A. $ZY plane$
View full question & answer→MCQ 271 Mark
The current through a wire varies with time as $I=I_0+\alpha t$ where $I_0=20 A$ and $\alpha=3 As ^{-1}$. Find the charge that flows across a cross-section of the wire in first 10 seconds.
- ✓
$350{ }^{\circ} C$
- B
$300{ }^{\circ} C$
- C
$200{ }^{\circ} C$
- D
$150{ }^{\circ} C$
AnswerCorrect option: A. $350{ }^{\circ} C$
View full question & answer→MCQ 281 Mark
A steady current flows in a metallic conductor of non-uniform cross-section. Which of the following quantities is constant along the conductor?
MCQ 291 Mark
The value of the temperature co-efficient of resistivity $(\alpha)$ is $\qquad$ for metals.
View full question & answer→MCQ 301 Mark
Which of the following physical quantity has unit $m ^2 V^{-1} s^{-1}$ ?
View full question & answer→MCQ 311 Mark
Two capacitors when connected in series, their equivalent capacitance is $3 \mu F$ and when they are connected in parallel their equivalent capacitance is $16 \mu F$. Their values are respectively __________ $\mu F$ and __________ $\mu F$.
- A
$16,1$
- B
$8,8$
- C
$8,16$
- ✓
$4,12$
AnswerCorrect option: D. $4,12$
View full question & answer→MCQ 321 Mark
An electron is accelerated by a potential difference of $\Delta V =2$ volts. The energy gained by it would be _________ eV.
- ✓
$2 eV$
- B
$1.5 eV$
- C
$1 eV$
- D
$0.5 eV$
AnswerCorrect option: A. $2 eV$
View full question & answer→MCQ 331 Mark
The electric potentials at two points $(0,3) mm$ and $(0,4) mm$ in the region in which electric field $\vec{E}=20 \hat{ i } NC ^{-1}$ are $V_A$ and $V_B$ respectively then,
- A
$V _{ A }> V _{ B }$
- B
$V _{ A } < V _{ B }$
- ✓
$V _{ A }= V _{ B }$
- D
None of the given choices
AnswerCorrect option: C. $V _{ A }= V _{ B }$
View full question & answer→MCQ 341 Mark
The electric potential at a distance __________ due to the charge $4 \times 10^{-7} C$ is $4 \times 10^4 V$.
View full question & answer→MCQ 351 Mark
The number of electric field lines coming out of charge __________, kept in a vacuum is $1.13 \times 10^{11}$. $\left(\varepsilon_0=8.85 \times 10^{-12} C ^2 N^{-1} m^{-2}\right)$
View full question & answer→MCQ 361 Mark
The dimensions of $\frac{ Ke ^2}{ Gm _{ g } m }$ is __________ .
AnswerCorrect option: A. $M^0 L^0 T ^0 A^0$
View full question & answer→MCQ 371 Mark
An electric field line is a curve drawn in such a way that the tangent dram! any point on the curve gives __________ at that point.
- A
magnitude of the electric field
- ✓
direction of the electric field
- C
both magnitude and direction of electric field
- D
none of the given choices
AnswerCorrect option: B. direction of the electric field
View full question & answer→MCQ 381 Mark
A uniformly charged conducting sphere of 2.4 m diameter has a surface che density of $80 \mu C m ^{-2}$. The charge on the sphere is mC .
- A
$4.51$
- ✓
$1.45$
- C
$5.41$
- D
$45.1$
AnswerCorrect option: B. $1.45$
View full question & answer→MCQ 391 Mark
If a body contains $n$, electrons and $n$, protons, the total amount of charge cote body is __________ .
View full question & answer→MCQ 401 Mark
When $p-n$ junction is kept in forward bias, __________ .
- A
barrier potential increases
- B
current due to majority charge carrier decreases
- ✓
barrier potential decreases
- D
none of the given choices
AnswerCorrect option: C. barrier potential decreases
View full question & answer→MCQ 411 Mark
If $n_e$ number of free electrons, $n_h=$ number of holes then for pure semi conducting.
- A
$n_e>n_b$
- ✓
$n_c=n_h$
- C
$n _{ h }> n _{ e }$
- D
$n_e=n_i^2$
AnswerCorrect option: B. $n_c=n_h$
View full question & answer→MCQ 421 Mark
If the radius of nucleus is $3.6 f_m$, then the atomic mass number of its atom __________ unit.
View full question & answer→MCQ 431 Mark
Nuclear force is acting between…
MCQ 441 Mark
The radius of the nucleus of ${ }_{13}^{27} Al$ is __________ .
- A
$R _0$
- ✓
$3 R _0$
- C
$R _0^{\frac{1}{3}}$
- D
$R_0^3$
AnswerCorrect option: B. $3 R _0$
View full question & answer→MCQ 451 Mark
Which one of the following spectral line lies in Ultraviolet region?
MCQ 461 Mark
The energy required to excite an electron of the hydrogen atom from its ground state to second excited sate is _________ eV.
- A
$10.2$
- B
$13.6$
- ✓
$12.09$
- D
$3.40$
AnswerCorrect option: C. $12.09$
View full question & answer→MCQ 471 Mark
The dimensions of $\frac{m e^4}{8 \varepsilon_0^2 h^3 c}$ is __________ .
- A
$M ^0 L^0 T^0$
- ✓
$M ^0 L^{-1} T^0$
- C
$M ^0 L^1 T^0$
- D
$M ^{-1} L^0 T^0$
AnswerCorrect option: B. $M ^0 L^{-1} T^0$
View full question & answer→MCQ 481 Mark
Photons are ________ electrically.
- A
- ✓
- C
- D
some time positively charged and some time negatively charged
View full question & answer→MCQ 491 Mark
Value of work function depend on __________ .
- A
- B
- C
type of metal surface and surface area.
- ✓
type of metal and type of metal surface.
AnswerCorrect option: D. type of metal and type of metal surface.
View full question & answer→MCQ 501 Mark
The slope of the graph of the stopping potential $\left( V _0\right) \rightarrow$ frequency $(v) f$ the photoelectric effect is equal to __________ .
- A
$h$
- B
- ✓
$\frac{h}{e}$
- D
$\frac{h}{2 \pi}$
AnswerCorrect option: C. $\frac{h}{e}$
View full question & answer→