Free Photons and the Particle Model of Light MCQs with Answers

• A. Infinite
• B. Zero
• C. 1.6 x 10^-27 kg
• D. 3 x 10^8 kg

Explanation: The rest mass of a photon is 0. This is because photons are particles of light and they always move at the speed of light in a vacuum.

• A. 1.02 MeV
• B. 1.51 MeV
• C. 0.52MeV
• D. 0.051MeV

Explanation: The minimum energy required by a photon to create an electron-positron pair is equal to 1.02 MeV . This process is known as pair production,

• A. 90⁰
• B. 180⁰
• C. 0⁰
• D. 45⁰

Explanation: Here is the explanation of the correct optionλ = (1-cosθ) (use substitute technique)θ = 180λ = 2h/mc

• A. 4.2 eV
• B. 2.1 eV
• C. 1.2 eV
• D. 0.98 eV

Explanation: The energy of a photon can be calculated using the formula E = hc/λ, where h is Planck's constant (4.135667696 × 10-15 eV·s), c is the…

• A. Pair production
• B. Pair annihilation
• C. Compton's effect
• D. Photoelectric effect

Explanation: B) Pair annihilation: This process occurs when a particle and its antiparticle (like an electron and a positron) collide and convert their…

• A. same for all types of materials.
• B. different for same types of materials.
• C. less than zero for all types of materials.
• D. different for different types of materials.

Explanation: The threshold frequency (\(f_{0}\)) is the minimum frequency of incident light required to cause the emission of electrons from a metal…

• A. dual nature.
• B. wave nature only.
• C. particle nature only.
• D. electromagnetic nature.

Explanation: The photoelectric effect and the Compton effect both provide strong evidence that light possesses a dual nature (A).

• A. Velocity
• B. Intensity
• C. Frequency
• D. Wavelength

Explanation: In the photoelectric effect, electrons are emitted from a metal surface when the frequency of the incident light exceeds a certain…

• A. saturation region.
• B. intensity of the incident light.
• C. frequency of the incident light.
• D. surface temperature of the metal surface.

Explanation: In the photoelectric effect, the maximum kinetic energy of the emitted photoelectrons depends on the frequency of the incident light.

• A. Pair production.
• B. Compton's effect.
• C. Photoelectric effect.
• D. Annihilation of matter.

Explanation: The correct answer is 'Pair production.' This phenomenon occurs when a high-energy photon interacts with a nucleus and transforms into an…

• A. I only.
• B. II only.
• C. I and III.
• D. II and III.

Explanation: Compton's experiment is a pivotal demonstration of the particle nature of light.

• A. value of potential difference
• B. velocity of the emitted electrons
• C. kinetic energy of the emitted electrons
• D. number of electrons emitted per second

Explanation: When light with higher intensity falls on a metal surface, more electrons are ejected from the surface, leading to an increase in the…

• A. Has shiny surface.
• B. Has low work function.
• C. Has high threshold energy.
• D. Is sensitive to the frequency of light.

Explanation: The most suitable metal for photoelectric emission is characterized by a low work function.

• A. X = 0 V.
• B. X = 2 V.
• C. X > 2 V.
• D. 0 V < X < 2 V.

Explanation: The energy of light is inversely related to its wavelength, according to the equation E = hc/λ, where h is Planck's constant, c is the…

• A. Inversely proportional to the frequency of the incident light.
• B. Directly proportional to the frequency of the incident light.
• C. Inversely proportional to the intensity of the incident light.
• D. Directly proportional to the intensity of the incident light.

Explanation: In the photoelectric effect, the number of photoelectrons ejected from a metallic surface is directly proportional to the intensity of the…

• A. Pair production.
• B. Pair annihilation.
• C. Compton's effect.
• D. Uncertainty principle.

Explanation: The correct answer is Compton's effect. This phenomenon occurs when X-rays are scattered by electrons, resulting in a change in the…

• A. Increase the frequency of the incident light
• B. Decrease the frequency of the incident light
• C. Increase the intensity of the incident light
• D. Use a different material with a higher work function

Explanation: The photoelectric effect occurs when photons with energy equal to or greater than the material's work function strike the surface and…

• A. Compton effect.
• B. Pair production.
• C. Photoelectric effect.
• D. Annihilation of matter.

Explanation: The correct answer is annihilation of matter. This process involves the collision of a particle with its antiparticle, leading to their…

• A. Velocity of photons.
• B. Threshold frequency.
• C. Intensity of light source.
• D. Frequency of light source.

Explanation: In the photoelectric effect, the number of photoelectrons ejected from a material is increased by increasing the intensity of the light…

• A. I. Compton's effect and II. photoelectric effect.
• B. I. Compton's effect and IV. pair production of matter.
• C. II. Photoelectric effect and III. annihilation of matter.
• D. III. Annihilation of matter and IV. pair production of matter.

Explanation: Einstein's mass-energy relation, expressed as E=mc², is experimentally proven by phenomena that involve the conversion between mass and…