CBES Board Class 12 MCQ Quiz Hub

1. Who established that electric charge is quantised?
J.J. Thomson
William Crookes
R.A. Millikan
Wilhelm Rontgen

2. Cathode rays were discovered by
Maxwell Clerk James
Heinrich Hertz
William Crookes
J.J. Thomson

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?
Thermionic emission
Field emission
Photoelectric emission
All of these

4. The phenomenon of photoelectric emission was discovered in 1887 by
Albert Einstein
Heinrich Hertz
Wilhelm Hallwachs
Philipp Lenard

5. 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
blue light
heat rays
infrared light
red light

6. Which of the following statements is correct regarding the photoelectric experiment?
The photocurrent increases with intensity of light.
Stopping potential increases with increase in intensity of incident light.
 The photocurrent increases with increase in frequency.
All of these

7.  In photoelectric effect, the photocurrent
depends both on intensity and frequency of the incident light.
does not depend on the frequency of incident light but depends on the intensity of the inci-dent light.
decreases with increase in frequency of inci-dent light.
increases with increase in frequency of inci-dent light.

8. The maximum value of photoelectric current is called
 base current
 saturation current
collector current
 emitter current

9. In photoelectric effect, the photoelectric current is independent of
intensity of incident light
potential difference applied between the two electrodes
the nature of emitter material
frequency of incident light

10. In photoelectric effect, stopping potential depends on
frequency of incident light
nature of the emitter material
 intensity of incident light
both (1) and (2)

11. 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
depends on the intensity of the incident radi-ation.
depends on the nature of the metal and also on the intensity of incident radiation.
is same for all metals and independent of the intensity of the incident radiation.
depends on the nature of the metal.

12. Which phenomenon best supports the theory that matter has a wave nature?
 Electron momentum
Electron diffraction
Photon momentum
Photon diffraction

13. The first model of atom in 1898 was proposed by
Ernst Rutherford
Albert Einstein
 J.J. Thomson
Niels Bohr

14. In Geiger-Marsden scattering experiment, the trajectory traced by an a-particle depends on
number of collision
number of scattered a-particles
impact parameter
none of these

15. In the Geiger-Marsden scattering experiment, is case of head-on collision the impact parameter should be
maximum
minimum
infinite
zero

16. Which of the following spectral series falls within the visible range of electromagnetic radiation?
Lyman series
Balmer series
Paschen seriee
Pfund series

17. The first spectral series was discovered by
Balmer
Lyman
 Paschen
Pfund