Number of ejected photoelectron increases with increase

Options

A. in intensity of light
B. in wavelength of light
C. in frequency of light
D. never

Answer

To solve the question about the factors affecting the number of ejected photoelectrons, we can break it down step by step.

### Step 1: Understand the Photoelectric Effect
The photoelectric effect describes how electrons are ejected from a material when it is exposed to light (photons). The key parameters involved are the intensity of the light, the wavelength, and the frequency.

### Step 2: Analyze the Effect of Intensity
- **Intensity** refers to the amount of energy the light carries per unit area per unit time. Increasing the intensity means more photons are hitting the surface.
- More photons mean more interactions with electrons in the material. Therefore, if the intensity increases, the number of ejected photoelectrons will also increase.

### Step 3: Analyze the Effect of Wavelength
- **Wavelength** is inversely related to frequency (higher frequency means shorter wavelength).
- Increasing the wavelength means decreasing the frequency. If the wavelength is too long, it may not have enough energy to eject electrons at all, according to the photoelectric effect threshold.

### Step 4: Analyze the Effect of Frequency
- **Frequency** is directly related to the energy of the photons (E = hf, where h is Planck's constant).
- While increasing frequency increases the energy of individual photons, it does not increase the number of photons hitting the surface. Each photon still interacts with only one electron. Therefore, increasing frequency does not increase the number of ejected photoelectrons.

### Conclusion
From the analysis, we can conclude that:
- The number of ejected photoelectrons increases with an increase in **intensity** of the incident light.

### Final Answer
The correct answer is: **Intensity**.

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