Free Photons and the Particle Model of Light MCQs with Answers
196 Photons and the Particle Model of Light MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
Last updated
196 questions · page 5 of 10
- A. minimum frequency
- B. angular frequency
- C. maximum frequency
- D. threshold frequency
Explanation: There is a minimum frequency below which no electrons are emitted however intense the light may be.
Correct answer: threshold frequency- A. Frequency of incident light
- B. nature of material
- C. Intensity of incident light
- D. Frequency of light and nature of material
Explanation: The threshold frequency depends upon the nature of the metal. It is different for different metals.
Correct answer: nature of material- A. The electrons coming out of the metal surface with minimum energy
- B. The electrons coming out of the metal surface with full surplus energy (without losing any energy during collisions with the atoms of metal)
- C. The photons of light that reflect back from the metal surface
- D. All the electrons that come out of the metal surface
Explanation: If the energy of the photon is greater than the work function, then a part of it is used in escaping an electron from the metal surface.
Correct answer: The electrons coming out of the metal surface with full surplus energy (without losing any energy during collisions with the atoms of metal)- A. photo-voltaic cell
- B. photo-cell
- C. photo-phone
- D. photo-door
Explanation: A photocell is a device which converts light energy into electrical energy. It works on the photoelectric effect.
Correct answer: photo-cell- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Photo electric current does not depend upon frequency of photon.
Correct answer: Option A- A. Annihilation of matter
- B. Pair production
- C. Production of X-rays
- D. Nuclear fission
Explanation: The reverse process of the photoelectric effect is b) pair production. The photoelectric effect involves the emission of electrons from a…
Correct answer: Production of X-rays- A. The photoelectric current will decrease
- B. The photoelectric current will increase
- C. The stopping potential will decrease
- D. The stopping potential will increase
Explanation: The correct option is c) The stopping potential will increase if the wavelength of the incident radiation in a photoelectric experiment is…
Correct answer: The stopping potential will increase- A. The number of electrons emitted is a quarter of the initial number
- B. The number of electrons emittedis half the initial number
- C. Each electron emitted carries one quarter of initial energy
- D. Each emitted electron carries half the initial energy
Explanation: If distance from source becomes double then intensity of light and number of emitted electrons reduce to one fourth.
Correct answer: Each emitted electron carries half the initial energy- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: After the threshold frequency (K.E)e ∝ Frequency of incident light. The graph should be a straight line: In the photoelectric effect, the…
Correct answer: Option D- A. -2 V
- B. -4 V
- C. -3 V
- D. -1 V
Explanation: Stopping potential is that negative potential for which photo electric current is zero.
Correct answer: -4 V- A. The frequency of the incident light
- B. Their potential energy
- C. The number of photons that hit the sample
- D. Their kinetic energy
Explanation: No of electrons ejected ∝ intensity of light (No of photons)
Correct answer: The frequency of the incident light- A. The value of saturation current increases
- B. No effect
- C. The value of stopping potential increases
- D. The value of stopping potential decreases
Explanation: Please note that the correct option for the changes observed during Einstein's Photoelectric Experiment when the frequency of the incident…
Correct answer: The value of saturation current increases- A. As intensity increases, the photoelectric current increases
- B. As the intensity increases, the photoelectric current decreases
- C. As the intensity decreases, the photoelectric current becomes twice
- D. No effect
Explanation: Since each incident photon ejects one photoelectron from a metal surface, therefore, the number of photoelectrons emitted depends on the…
Correct answer: As intensity increases, the photoelectric current increases- A. As intensity increases, stopping potential increases linearly
- B. As intensity increases, stopping potential decreases linearly
- C. As intensity decreases, stopping potential increases exponentially
- D. No effect
Explanation: Changing the intensity of incident radiation does not affect the stopping potential.
Correct answer: No effect- A. frequency of incident light
- B. Intensity of incident light
- C. nature of cathode rays
- D. none of these
Explanation: Kinetic energy of photo electrons does not depend upon intensity of light but it depends upon energy (frequency) of photon
Correct answer: frequency of incident light- A. Four times
- B. Double
- C. Half
- D. Zero
Explanation: When the frequency of incident light is halved of its original value i.e. 1.5vo then it becomes less than the threshold value.
Correct answer: Zero- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Photoelectric current ∝ Intensity of incident light In the photoelectric effect, the photoelectric current is directly proportional to the…
Correct answer: Option A- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: From the incident photon energy, the electron needs a certain minimum energy called the work function "Φ" to escape from the metal surface…
Correct answer: Option D- A. One
- B. More than two
- C. Two
- D. Electron emission is not possible
Explanation: Here incident energy of photon < work function So, the photoelectric effect will not start.
Correct answer: Electron emission is not possible- A. Compton equation
- B. Plank's equation
- C. Newton's equation
- D. Photoelectric equation
Explanation: The photoelectric equation is hf=hfo +K.E. (max) The above equation is also called Einstein's photoelectric equation.
Correct answer: Photoelectric equation