Modern Physics MCQs

By: Prof. Dr. Fazal Rehman | Last updated: May 20, 2025

1. : In a photocell, cesium is coated with an oxidized silver cathode that emits electrons for
(A) Visible light
(B) Ultraviolet
(C) Infrared light
(D) X-rays

2. : An inertial frame of reference is a frame
(A) In which the first law of motion and inertia are valid
(B) Where inertia is valid
(C) Which is not moving with uniform velocity
(D) Both A and B

3. : The rest mass energy of an electron is
(A) 1.02 MeV (Million Electron Volts)
(B) 0.511 KeV (Kilo Electron Volts)
(C) 0.511 MeV
(D) 2.02 MeV

4. : According to the theory of relativity, the mass of an object is equal to
(A) Depends on particles
(B) Speed of light
(C) Volume of the object
(D) Area of the object

5. : According to the special theory of relativity, which one is not an absolute quantity?
(A) Time and mass
(B) Mass
(C) Height
(D) None of the above

6. : The special theory of relativity treats problems involving which type of frame of reference?
(A) Inertial frame of reference
(B) Non-inertial frame of reference
(C) Non-accelerated frame of reference
(D) Accelerated frame of reference

7. : Quantum effects are important only when observing
(A) Small objects
(B) Very large objects
(C) Atomic spectra
(D) Atomic size objects

8. : A statement saying that energy is radiated or absorbed in discrete packets is given by
(A) Planck (1.616229(38) × 10⁻³⁵ meters)
(B) Einstein
(C) Stephen
(D) Wien

9. : The phenomena that cannot be understood with the framework of classical physics are
(A) Blackbody radiation, atomic spectra
(B) Atomic spectra
(C) Inertial frame
(D) None of the above

10. : The behavior of matter on an atomic level cannot be explained in which of the following?
(A) Modern physics
(B) Classical physics
(C) Relativistic mechanics
(D) Atomic spectra

11. : The maximum kinetic energy (K.E) of photoelectrons depends upon the light’s
(A) Intensity
(B) Frequency
(C) Wavelength
(D) Energy

12. : Earth can be considered as which type of frame?
(A) Inertial frame
(B) Non-inertial frame
(C) Accelerated frame
(D) Velocity frame