Physics MCQs GK objective Questions GK test Set – 65

Question 1.

Resistance of human body in dry condition

A. 10 ohm
B. 1000 ohm
C. 10000 ohm
D. 100000 ohm

Ans: D. 100000 ohm

Question 2.

A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of the emf’s is :

A. 3:4
B. 5:4
C. 5:1
D. 3:2

Ans: D. 3:2

Question 3.

The ”Choke’ used with a tube light is basically

A. An inductor
B. A capacitor
C. A transformer
D. A resistor

Ans: A. An inductor

Question 4.

The energy of a photon, whose momentum is 10 MeV/c, where c is the speed of light, is given by

A.10 MeV
B. 100 MeV
C. 1 MeV
D. 0.1 MeV

Ans: A.10 MeV

Question 5.

The purpose of choke in a fluorescent lamp is :

A. To increase the current flow
B. To decrease the current flow
C. To decrease the resistance
D. Ro decrease the voltage momentarily

Ans: B. To decrease the current flow

Question 6.

Suppose voltage V is applied across a resistance R. The power dissipated in the resistance is P. Now the same voltage V is applied across a parallel combination of three equal resistors each of resistance R. Then the power dissipated in the second case will be

A. P
B. 3P
C. P/3
D. 2p/ 3

Ans: B. 3P

Question 7.

For photoelectric effect to take place, the metal used as the cathode should have __

A. High melting point
B. Low melting point
C. Low work function
D. Low resistance

Ans: C. Low work function

Question 8.

The energy of a photon varies directly with its

A. Wave length
B. Frequency
C. Speed
D. None of the above

Ans: B. Frequency

Question 9.

An electron and a proton starting from rest get accelerated through potential difference of 100 kV. The final speed of the electron and the proton are Ve and Vp respectively. Which of the following relations is correct?

A. Ve > Vp
B. Ve < Vp
C. Ve = Vp
D. Cannot be determined

Ans: A. Ve > Vp

Question 10.

A galvanometer can be converted into a voltmeter by connecting with it a

A. High resistance in parallel
B. Low resistance on parallel
C. High resistance on series
D. Low resistance in series

Ans: C. High resistance on series

Question 11.

Which phenomena shows the particle nature of light?

A. Diffraction
B.Interference
C. Photoelectric effect
D. Polarisation

Ans: C. Photoelectric effect

Question 12.

A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?

A. The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
B. Both the photons have different energies.
C. The speeds of both the photons in vacuum are different
D. The frequency of X-ray photon is higher than the frequency of visible radiation photon.

Ans: C. The speeds of both the photons in vacuum are different

Question 13.

Superconductors are those elements

A. Whose conductivity is intermediate between metals and insulators
B. Whose resistance falls almost to zero at very low temperatures
C. Which turn into insulators at very low temperatures
D. Which conduct electricity only at super-high temperatures

Ans: B. Whose resistance falls almost to zero at very low temperatures

Question 14.

In superconductors, the energy gap is due to

A. Electron-electron interaction
B. Electron-phonon interaction
C. Phonon-phonon interaction
D. Electron-photon intercation

Ans: B. Electron-phonon interaction

Question 15.

According to the quantum theory of light, the energy of light is carried in discrete units are called

A. Photoelectrons
B. Protons
C. Electrons
D. Photons

Ans: D. Photons

Question 16.

The threshold frequency is the frequency below which :

A. Photo current increases with voltage
B. Photo current decreases with voltage
C. Photo electric emission is not possible
D. Photo current is constant

Ans: C. Photo electric emission is not possible

Question 17.

A device used for converting a.c. into d.c. is called

A. Transformer
B. Rectifier
C. Induction coil
D. Dynamo

Ans: B. Rectifier

Question 18.

Electrical Pressure is also called

A. Current
B. Voltage
C. Resistance
D. Power

Ans: B. Voltage

Question 19.

Photon is the fundamental unit/quantum of

A. Gravitation
B. Electricity
C. Magnetism
D. Light

Ans: D. Light

Question 20.

Which of the following supports particle nature of photons ?

A. Diffraction
B. Polarization
C. Photoelectric effect
D. Interference

Ans: C. Photoelectric effect

Physics GK MCQs all set

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