If intensity of incident light is increased in photo electric effect then which of the following is true ?

Options

A. Maximum KE of ejected electron will increase
B. Work function will remain unchanged
C. Stopping potential will decrease
D. Maximum KE of ejected electron will decrease

Answer

To solve the question regarding the effect of increasing the intensity of incident light in the photoelectric effect, we will analyze the relevant concepts step by step.

### Step 1: Understand the Concept of Intensity
Intensity of light is defined as the power per unit area. In the context of the photoelectric effect, an increase in intensity means that more photons are striking the surface per unit time.

**Hint:** Remember that intensity is related to the number of photons hitting a surface.

### Step 2: Relationship Between Intensity and Photons
The intensity of incident light is directly proportional to the number of photons per unit time. Therefore, if the intensity increases, the number of photons hitting the surface also increases.

**Hint:** Think about how more photons can lead to more electrons being ejected.

### Step 3: Photoelectric Effect Basics
In the photoelectric effect, when light of sufficient energy (frequency) strikes a material, it can eject electrons from that material. The energy of each photon is given by the equation \(E = h \nu\), where \(h\) is Planck's constant and \(\nu\) is the frequency of the light.

**Hint:** Recall that the energy of a photon is determined by its frequency, not its intensity.

### Step 4: Einstein's Photoelectric Equation
Einstein's photoelectric equation states:
\[ KE_{\text{max}} = h \nu - \phi \]
where \(KE_{\text{max}}\) is the maximum kinetic energy of the ejected electrons, \(h \nu\) is the energy of the incident photons, and \(\phi\) is the work function of the material.

**Hint:** Focus on how the maximum kinetic energy is influenced by the frequency of light, not the intensity.

### Step 5: Effect of Intensity on Kinetic Energy and Work Function
From the photoelectric equation, we can see that the maximum kinetic energy of the ejected electrons depends on the energy of the photons (which is related to their frequency) and the work function of the material. The intensity of light does not affect the energy of individual photons or the work function.

**Hint:** Remember that the work function is a property of the material and does not change with light intensity.

### Step 6: Analyzing the Options
1. **Maximum kinetic energy of ejected electron will increase** - This is false because kinetic energy does not depend on intensity.
2. **Work function will remain unchanged** - This is true as the work function is a material property.
3. **Stopping potential will decrease** - This is false because stopping potential does not depend on intensity.
4. **Kinetic energy will increase** - This is false for the same reason as option 1.

**Hint:** Evaluate each option based on your understanding of how intensity affects the photoelectric effect.

### Conclusion
The correct answer is that the work function will remain unchanged when the intensity of the incident light is increased.

**Final Answer:** Option 2: The work function will remain unchanged.