2nd Year Physics Chapter 6 TestQUANTUM PHYSICS

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. Quanta is the plural form of:

   1. Quantum

   2. Quark

   3. Quarkum

   4. Quantae

2. The current measured in a photoelectric circuit when light shines on the cathode is known as:

   1. Alternating current

   2. Thermal current

   3. Photoelectric current 

   4. Saturation voltage

3. If the intensity of the incident light is increased, what happens to the photoelectric current?

   1. It increases

   2. It decreases

   3. It remains unchanged

   4. It drops to zero

4. Using uncertainty principle, it can be proved that:

   1. Lght has particle nature

   2. Light has wave nature

   3. Electron lies out of the nucleus

   4. There is always uncertainty in measuring accurately energy and momentum for atomic particles

5. The wave nature of electrons is supported by experiments on:

   1. Lne spectrum of atoms

   2. The production of X-rays

   3. Photoelectric effect

   4. Electron diffraction by crystalline material

6. Compton treated the collision between an X-ray photon and an electron similar to a collision between:

   1. Light waves

   2. Two water droplets

   3. Billiard balls

   4. Magnetic poles

7. According to the classical electromagnetic wave theory of light, increasing light intensity should increase the:

   1. Threshold frequency

   2. Amplitude of the electric vector / energy of electrons

   3. Work function of the metal

   4. Speed of light

8. Which of the following has the most energetic photons?

   1. Light waves

   2. Microwaves

   3. X-rays

   4. Gamma rays

9. When the potential of plate A is made more negative with respect to plate C, the photoelectric current:

   1. Increases linearly

   2. Remains constant

   3. Decreases 

   4. Becomes infinite

10. Einstein extended whose quantum theory to explain the photoelectric effect?

    1. Newton's

    2. Maxwell's

    3. Max Planck's

    4. Rutherford's