Class/Course  Class XII
Subject  Physics
Total Number of Question/s  5154
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1. Electric Charges and Fields  Quiz
1. A positive point charge 50μC is located in the plane xy at a point with radius vector $\vec{r}_{0}$ = $2\hat{i} + 3\hat{j}$. The electric field $\vec{E}$ at a point with radius vector $\vec{r}$ = $8\hat{i}  5\hat{j}$, where r_{0} and r are expressed in meter, is
a) $\left (1.4\hat{i}  2.6\hat{j}\right )kNC^{1}$
b) $\left (1.4\hat{i} + 2.6\hat{j}\right )kNC^{1}$
c) $\left (2.7\hat{i}  3.6\hat{j}\right )kNC^{1}$
d) $\left (2.7\hat{i} + 3.6\hat{j}\right )kNC^{1}$
2. Four point + ve charges of same magnitude (Q) are placed at four corner of a rigid square frame as shown in figure. The plane of the frame is perpendicular to Z axis. If ave point charge is placed at a distance z away from the above frame (z<
a) ve charge oscillates along the Z axis
b) It moves away from the frame.
c) It moves slowly towards the frame and stays in the plane of the frame.
d) It passes through the frame only once.

2. Electrostatic Potential and Capacitance  Quiz
1. Capacitance of a parallel plate capacitors is 4/3 times its original value, if a dielectric slab of thickness t = d/2 is inserted between the plates ]. The dielectric constant of the slab is
a) 2
b) 6
c) 4
d) 8
2. A capacitor of capacitance C_{0} is charged to a potential V_{0} and then isolated. A small capacitor C is then charged from C_{0}, discharged and charged again; the process being repeated n times. Due to this, the potential of the larger capacitor is decreased to V. The value of C is
a) $C_{0}\left (\frac{V_{0}}{V} \right )^{1/n}$
b) $C_{0}\left [\left (\frac{V_{0}}{V} \right )^{1/n}  1 \right ]$
c) $C_{0}\left [\left (\frac{V_{0}}{V} \right )  1 \right ]^{n}$
d) $C_{0}\left [\left (\frac{V_{0}}{V} \right )^{n} + 1 \right ]$

3. Current Electricity  Quiz
1. In cells each of emf E and internal resistance r send the same current through an external resistance R whether the cells are connected in series or in parallel. The
a) R = nr
b) R = r
c) r = n R
d) R = √nr
2. Sixteen resistors, rach of resistance 16Ω , are connected in the circuit as shown in figure. The net resistance between A and B is
a) 1Ω
b) 2ωΩ
c) 3Ω
d) Ω

4. Moving Charges and Magnetism  Quiz
1. Consider six wires coming into or out of the page, all with the same current. Rank the line integral of the magnetic field (from most positive to most negative) taken counterclockwise around each loop shown.
a) B > C > D > A
b) B > C = D > A
c) B > A > C = D
d) C > B = D > A
2. A beam of electrons passes undeflected through mutually perpendicular electric and magnetic fields. If electric field is switched off, and the same magnetic field is maintained, the electrons move
a) In a circular orbit
b) Along a parabolic path
c) Along a straight line
d) In an elliptical orbit

5. Magnetism and Matter  Quiz
1. Which of the following units denotes the dimensions ML^{2}/Q^{2}, where Q denotes the electric charge?
a) Weber (Wb)
b) Wb/m^{2}
c) Henry (H)
d) H/m
2. Two short bar magnets of magnetic moments M each are arranged at the opposite corners of a square of sid d such that their centers coincide with the corners and their axes are parralel. If the like poles are in the same direction, the magnetic induction at any other corner of the square is
a) μ_{0}/4π M/d^{3}
b) μ_{0}/4π 2M/d^{3}
c) μ_{0}/4π M/2d^{3}
d) μ_{0}/4π M^{3}/d^{3}

6. Electromagnetic Induction  Quiz
1. Two coils of self inductance L_{1} and L_{2} are placed so close together that effective flux in one coil is completely linked with other. If M is mutual inductance between them, then M =
a) L_{1}L_{2}
b) L_{1}/L_{2}
c) (L_{1}L_{2})^{2}
d) (√L_{1}L2)
2. As a result of change in the magnetic flux linked to the closed loop shown in the figure, an emf V volt is induced in the loop. The work done (joule) in taking a charge Q coulomb once along the loop is
a) QV
b) Zero
c) 2QV
d) QV/2

7. Alternating Current  Quiz
1. In an a.c. circuit the e.m.f.(e) and the current (i) at any instant are given respectively by
e  E_{0} sin ωt
The average power in the circuit over one cycle of a.c. is
a) E_{0}I_{0}
b) E_{0}I_{0}/2
c) (E_{0}I_{0})sinφ
d) (E_{0}I_{0}/2)cosφ
2. A 50 W, 100 V lamp is to be connecteed to an ac mains of 200 V, 500 Hz. What capacitor is essential to be put in series with the lamp?
a) $\frac{25}{\sqrt{2}}\mu F$
b) $\frac{50}{\pi \sqrt{3}}\mu F$
c) $\frac{50}{\sqrt{2}}\mu F$
d) $\frac{100}{\pi \sqrt{3}}\mu F$

8. Electromagnetic Waves  Quiz
1. A stepup transformer operates on a 230V line and supplies current of 2A to a loaf. The ratio of the primary and secondary windings is 1:25. The current in the primary coil is
a) 15 A
b) 50 A
c) 25 A
d) 12.5 A
2. Which of the following radiations has the least wavelength?
a) X  rays
b) Y  rays
c) β  rays
d) α  rays

9. Ray Optics and Optical Instruments  Quiz
1. A convex lens A of focal length 20cm and a concave lens G of focal length 5 cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance d is cm will be
a) 25
b) 15
c) 30
d) 50
2. The time taken by light to pass through 4 mm thick glass slab of refractive index 1.5 will be (velocity of light in air = 3 x 10^{8} m/s)
a) 8 x 10^{11} s
b) 2 x 10^{11} s
c) 8 x 10^{8} s
d) 2 x 10^{8} s

10. Wave Optics  Quiz
1. In young s double slit experiment , the ycoordinates of central maxima and 10^{th} maxima are 2 cm and 5 cm, respectively . When the YDSE apparatus is immersed in a liquid of refractive index 1.5 , the corresponding ycoordinates will be
a) 2 cm, 7.5 cm
b) 3 cm, 6 cm
c) 2 cm, 4 cm
d) 4/3 cm, 103 cm
2. In young double slit experiment, the fringe width is β. If the entire arrangement is placed in a liquid of refractive index n, the fringe width becomes
a) β/n1
b) β/n
c) nβ
d) β/n+1

11. Dual Nature of Radiation and Matter  Quiz
1. The work function of a substance is 4.0 e V. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
a) 540 nm
b) 400 nm
c) 310 nm
d) 220 nm
2. The minimum orbital angular momentum of the electron in a hydrogen atom is
a) h
b) h/e
c) h/2π
d) h/λ

12. Nuclei  Quiz
1. The halflife of radium is 1500 years. In how many years will 1g of pure radium be reduced to one centigram?
a) 3.927 x 10^{2} years
b) 9.972 x 10^{2} years
c) 99.927 x 10^{2} years
d) 0.927 x 10^{2}
2. A radioactive sample S_{1} having an activity is μCi has twice the number of nuclei as another sample S_{2} which has an acitivity of 10μCi. The half lives of S_{1} and S_{2} can be
a) 20 years and 5 years, respectively
b) 20 years and 10 years, respectively
c) 10 years each
d) 5 years each

13. Semiconductor Electronics: Materials, Devices and Simple Circuit  Quiz
1. A semiconductor is formed by
a) Covalent bonds
b) Electrovalent bonds
c) Coordinate bonds
d) Metallic bonds
2. The given truth table is for which logic gate?
a) NAND
b) XOR
c) NOR
d) OR

14. Communication Systems  Quiz
1. In which frequencies range space waves are normally propagated
a) HF
b) VHF
c) UHF
d) SHF
2. Broadcasting antennas are generally
a) Omnidirectional type
b) Vertical type
c) Horizontal type
d) None of the above

15. Atoms  Quiz
1. When a hydrogen atom is raised from the ground state to fifth state :
a) both KE and PE increases
b) both KE and PE decrease
c) PE increases and KE decreases
d) PE decreases and KE increases
2. The recoil speed of hydrogen atom after it emits a photon in going from n = 2 state n = 1 state is nearly. [Take R_{∞} = 1.1 x 10^{7} m^{1} and and h = 6.63 x 10^{34} Js]
a) 1.5 ms^{1}
b) 3.3 ms^{1}
c) 4.5 ms^{1}
d) 6.6 ms^{1}

16. Electric flux and Gauss Law  Quiz
1. A hollow metallic sphere of radius 10cm is given a charge of 3.2 × 10^{9}C. The electric intensity at a point 4cm from the center is
a) 9 × 10^{9} NC^{1}
b) 299 NC^{1}
c) 2.88 NC^{1}
d) zero
2. The electric flux from a cube of edge l is φ. If an edge of the cube is made 2l and the charge enclosed is halved, its value will be
a) 4φ
b) 2φ
c) φ/2
d) φ

17. Electrical Measuring Instrument  Quiz
1. An ideal ammeter (zero resistance) and an ideal voltmeter (infinite resistance) are connected as shown in figure. The ammeter and the voltmeter readings are
a) 6.25A, 3.75V
b) 3.00A, 5V
c) 3.00A, 3.75V
d) 6.00A, 6.25V
2. Sensitivity of a potentiometer can be increased by
a) increasing the emf of the cell
b) increasing the length of the potentiometer
c) decreasing the length of the potentiometer
d) none of the above

18. Heating Effect of Current  Quiz
1. The operating temperature of the filament of lamp is 2000^{0}C. The temperature cofficient of the material of the filament is 0.005^{0}C^{1}. If the atmospheric temperature is 0^{0}C, then the current in the 100W  200V lamp when it is switched on is nearest to
a) 2.5 A
b) 3.5 A
c) 4.5 A
d) 5.5 A
2. A given resistor cannot carry currents exceeding 20A, without exceeding its maximum power dissipation ratings. By forced air cooling suppose that we increase the rate at which heat can be carried by a factor of 2. Now the maximum current that the resistor can carry is
a) 10A
b) 20$\sqrt{2}$A
c) 30$\sqrt{2}$A
d) 40A