NEET Physics: Dual Nature of Radiation questions with solutions

Q1. If wavelength of photon and electron is same then ratio of total energy of electron to total energy of photon would be:

1. \( \frac{\text { Velocity of electron }}{\text { Light's speed }} \)
2. \( \frac{\text { Light's speed }}{\text { Electon's speed }} \)
3. \( \frac{\text { Light's speed }}{\text { Velocity of electron }} \)
4. \( \frac{\text { Electron's speed }}{\text { Light's speed }} \)

Answer: \( \frac{\text { Velocity of electron }}{\text { Light's speed }} \)

For a photon, total energy is E = hc/λ. For an electron with the same wavelength, its momentum is p = h/λ, so its total energy in this context is proportional to pc = hc/λ times the speed ratio, giving E_e/E_γ = v/c. Hence the ratio is electron speed divided by light speed.

Q2. The photoelectric effect represent that

1. Light has a particle nature
2. Electron has a wave nature
3. Proton has a wave nature
4. None of the above

Answer: Light has a particle nature

The photoelectric effect shows that light delivers energy in quantized packets called photons, not as a purely continuous wave. This is why electrons are emitted only when the light frequency is high enough, supporting the particle nature of light.