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Wednesday, June 1, 2011

Physics For UPSC IAS

Physics For UPSC IAS
physics for IAS exam Practice on physics MCQ
Physics practice test UPSC IAS

1. The binary number 110000111101 corresponds to a hexadecimal number:
(a) CFD
(b) D3C
(c) DBF
(d) C3D
Ans. (d)

2. A gate with only one input and one output is:
(a) AN OR gate
(b) A NOT gate
(c) A NAND gate
(d) AN AND gate
Ans. (b)

3. Which one of the following statements is not true in case of Zener diode?
(a) There is no similarity between the forward characteristic curves of a diode and Zener diode
(b)A Zener diode has sharp breakdown-voltage
(c) A Zener diode is always reverse-biased
(d) The Zener diode is a heavily doped diode
Ans. (a)

4. A nibble is equal to:
(a) 4 bits
(b) 8 bits
(c) 2 bits
(d) 16 bits
Ans. (a)

5. For a diatomic gas having 3 translational and 2 rotational degrees of freedom, the energy is given by:
(a) 5/2kT
(b) 3/2kT
(c) 1/2kT
(d) kT
Ans. (a)

6. From van der Waals’ equation, one n deduce that the critical temperature Tc of a substance is proportional to:
(a) a /b
(b) b/a
(c) a/b2
(d) b/a2
Ans. (a)

7. Stefan’s law states that the radiation emitted by a black body is proportional to the:
(a) Average kinetic energy of a molecule
(b) Frequency cut-off in the Debye model
(c) Fourth power of the temperature in degree Celsius (To C)4
(d) Fourth power of the temperature in degree Kelvin (TK)4
Ans. (d)

8. The maximum value of the emissive power of a black body corresponds to a frequency v1 at T1K and v2 at T2K. It follows from Planck’s law of radiation that:
(a) T1/T2 = v1/v2
(b) T2/T1 = v1/v2
(c) T12/T22 = v1/v2
(d) T22/T12 = v1/v2
Ans. (a)

9. Which one of the following pairs is correctly matched?
(a) Diamagnetism………. .susceptibility is positive
(b) Paramagnetism……… susceptibility decreases with increasing temperature
(c) Ferromagnetism……... susceptibility is zero
(d) Anti-ferromagnetism…. susceptibility is infinite
Ans. (b)

10. Curie temperature of. Iron is that temperature below which it is : -
(a) Ferromagnetic
(b) Electrically conducting
(c) Superconducting
(d) Radioactive
Ans. (a)

11. An electric charge is surrounded by several other electric charges. The force exerted by one of the surrounding charges on this charge:
(a) Decreases because of the other charges
(b) Increases because of the surrounding charges
(c) Is independent of the presence of other charges
(d) Depends on the position of other charges
Ans. (c)

12. Two large parallel plates, separated by a distance of 3.0 mm have a capacitance of 10 pF and are charged to a potential of 12 V by a battery. The plates are disconnected from the battery and pulled apart to 5.0 mm. The potential difference between the plates is:
(a) 12V
(b) 20V
(c) Zero
(d) 7.2V
Ans. (b)

13. A circular wire loop of radius r is placed in a region of magnetic field B such that the plane of the loop makes an angle θ with the direction of B. Consider the following conditions in this regard:
1. Change in B with time
2. Change in r with time
3. B being non-uniform in space
4. Change in θ with time
The conditions for an induced emf in the loop would
(a) 1 and 4
(b) 1, 2 and 4
(c) 1 and 3
(d) 2, 3 and 4
Ans. (15)

14. A straight conductor of length 05 m is moved with a speed of 8 m/s perpendicular to a magnetic field of intensity .1.2 Wb/m2. The induced emf across the conductor is
(a) 2.4V
(b) 4.8V
(c) 9.6V
(d) 24V
Ans. (b)

15. The coefficient of mutual inductance of two coils is 0.5 H. If the current is increased from 2 A to 3 A in 0.01 sin the primary coil, then the induced emf in the secondary coil will be
(a) 100V
(b) 75V
(c) 50V
(d) 25 V
Ans. (c)

16. A direct current of 5 A is superimposed on an alternating current I 10 sin cot flowing through a wire. The effective value of the resulting current will be:
(a) 15/2 A
(b) 5√3A
(c) 5J√5A
(d) 15A
Ans. (b)

17. A coil of inductance 5.0 mH and negligible resistance is connected to an oscillator giving an output voltage of
e = l0sin (l00t)
The peak current in the circuit will be:.
(a) 2A
(b) 5A
(c) 10A
(d) 20A
Ans. (d)

18. An electromagnetic wave is propagating in a medium. The quantity √μ/e is the:
(a) Intrinsic impedance of the medium
(b) Square of the refractive index of the medium
(c) Refractive index of the medium
(d) Energy density
Ans. (a)

19. Sign of the Hall coefficient determines the:
(a) Nature of the charge carriers
(b) Magnitude of charge on the carriers
(c) Number density of carriers
(d) Average energy of charge carriers
Ans. (a)

20. If a cyclotron is used to accelerate-electrons, they can attain kinetic energies of the order of a few:
(a) TeV
(b) BeV
(c) MeV
(d) keV
Ans. (c)

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