R4RIN – MCQs, Mock Tests | CBES Board Class 12

Who established that electric charge is quantised?

1. J.J. Thomson
2. William Crookes
3. R.A. Millikan
4. Wilhelm Rontgen

✅ Correct Answer: 3

Cathode rays were discovered by

1. Maxwell Clerk James
2. Heinrich Hertz
3. William Crookes
4. J.J. Thomson

✅ Correct Answer: 3

The minimum energy required for the electron emission from the metal surface can be supplied to the free electrons by which of the following physical processes?

1. Thermionic emission
2. Field emission
3. Photoelectric emission
4. All of these

✅ Correct Answer: 4

The phenomenon of photoelectric emission was discovered in 1887 by

1. Albert Einstein
2. Heinrich Hertz
3. Wilhelm Hallwachs
4. Philipp Lenard

✅ Correct Answer: 2

A metal surface ejects electrons when hit by green light but nothing when hit by yellow light. The electrons will be ejected when the surface is hit by

1. blue light
2. heat rays
3. infrared light
4. red light

✅ Correct Answer: 1

Which of the following statements is correct regarding the photoelectric experiment?

1. The photocurrent increases with intensity of light.
2. Stopping potential increases with increase in intensity of incident light.
3. The photocurrent increases with increase in frequency.
4. All of these

✅ Correct Answer: 1

In photoelectric effect, the photocurrent

1. depends both on intensity and frequency of the incident light.
2. does not depend on the frequency of incident light but depends on the intensity of the inci-dent light.
3. decreases with increase in frequency of inci-dent light.
4. increases with increase in frequency of inci-dent light.

✅ Correct Answer: 2

The maximum value of photoelectric current is called

1. base current
2. saturation current
3. collector current
4. emitter current

✅ Correct Answer: 2

In photoelectric effect, the photoelectric current is independent of

1. intensity of incident light
2. potential difference applied between the two electrodes
3. the nature of emitter material
4. frequency of incident light

✅ Correct Answer: 4

In photoelectric effect, stopping potential depends on

1. frequency of incident light
2. nature of the emitter material
3. intensity of incident light
4. both (1) and (2)

✅ Correct Answer: 4

According to Einstein’s photoelectric equation, the graph of kinetic energy of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slope

1. depends on the intensity of the incident radi-ation.
2. depends on the nature of the metal and also on the intensity of incident radiation.
3. is same for all metals and independent of the intensity of the incident radiation.
4. depends on the nature of the metal.

✅ Correct Answer: 3

Which phenomenon best supports the theory that matter has a wave nature?

1. Electron momentum
2. Electron diffraction
3. Photon momentum
4. Photon diffraction

✅ Correct Answer: 2

The first model of atom in 1898 was proposed by

1. Ernst Rutherford
2. Albert Einstein
3. J.J. Thomson
4. Niels Bohr

✅ Correct Answer: 3

In Geiger-Marsden scattering experiment, the trajectory traced by an a-particle depends on

1. number of collision
2. number of scattered a-particles
3. impact parameter
4. none of these

✅ Correct Answer: 3

In the Geiger-Marsden scattering experiment, is case of head-on collision the impact parameter should be

1. maximum
2. minimum
3. infinite
4. zero

✅ Correct Answer: 1

Which of the following spectral series falls within the visible range of electromagnetic radiation?

1. Lyman series
2. Balmer series
3. Paschen seriee
4. Pfund series

✅ Correct Answer: 2

The first spectral series was discovered by

1. Balmer
2. Lyman
3. Paschen
4. Pfund

✅ Correct Answer: 1