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When the intensity of radiation incident...

When the intensity of radiation incident on photographic plate is increased keeping frequency constant, thenthe number and K.E. of photoelectrons emitted?

A

Remains same and increases

B

Increases and remains same

C

Decreases and remains same

D

Decreases and decreases

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the effect of increasing the intensity of radiation on the number and kinetic energy of photoelectrons emitted from a photographic plate while keeping the frequency constant, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the Concept of Photoelectric Effect**: The photoelectric effect describes the emission of electrons from a material (usually a metal) when it is exposed to light (or electromagnetic radiation). The energy of the incident photons must be greater than the work function of the material for electrons to be emitted. 2. **Identify Key Parameters**: - **Intensity (I)**: This is the power per unit area of the incident radiation. Increasing intensity means more photons are hitting the surface per unit time. - **Frequency (ν)**: This is the number of oscillations of the electromagnetic wave per second. In this case, the frequency is kept constant. - **Work Function (ϕ)**: This is the minimum energy required to eject an electron from the surface of the material. 3. **Effect of Increasing Intensity**: - When the intensity of the radiation is increased while keeping the frequency constant, the number of photons striking the surface increases. Since each photon can potentially eject one electron, the number of emitted photoelectrons will increase. 4. **Kinetic Energy of Photoelectrons**: - The kinetic energy (K.E.) of the emitted photoelectrons is given by the equation: \[ K.E. = hν - ϕ \] where \(h\) is Planck's constant, \(ν\) is the frequency of the incident light, and \(ϕ\) is the work function of the material. - Since the frequency \(ν\) is constant and the work function \(ϕ\) is a property of the material, the kinetic energy of the emitted photoelectrons will also remain constant. 5. **Conclusion**: - Therefore, when the intensity of radiation is increased while keeping the frequency constant, the number of photoelectrons emitted increases, but the kinetic energy of the photoelectrons remains the same. ### Final Answer: - **Number of photoelectrons emitted**: Increases - **Kinetic energy of photoelectrons**: Remains the same
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