The strength of photoelectric current is directly proportional to :

Options

A. Frequency of incident radiation
B. Intensity of incident radiation
C. Angle of incidence of radiation
D. Distance between anode and cathode

Answer

To solve the question regarding the strength of photoelectric current and its direct proportionality, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Photoelectric Effect**:
The photoelectric effect refers to the phenomenon where electrons are emitted from a material (usually a metal) when it is exposed to light (or electromagnetic radiation). The emitted electrons create a current when they are collected.

2. **Identifying Factors Affecting Photoelectric Current**:
The strength of the photoelectric current depends on several factors, including:
- The intensity of the incident radiation (light).
- The frequency of the incident radiation.
- The angle of incidence of the radiation.
- The distance between the cathode and anode.

3. **Analyzing Each Factor**:
- **Frequency of Incident Radiation**: The energy of the photons is given by \(E = h\nu\), where \(h\) is Planck's constant and \(\nu\) is the frequency. While increasing frequency increases the energy of the emitted electrons, it does not increase the number of emitted electrons if the intensity remains constant. Therefore, the current does not depend on frequency.

- **Intensity of Incident Radiation**: The intensity of the radiation is related to the number of photons striking the surface per unit time. Higher intensity means more photons, which leads to more electrons being emitted. Thus, the photoelectric current is directly proportional to the intensity of the incident radiation.

- **Angle of Incidence**: The angle at which light strikes the surface does not affect the number of photons hitting the surface if the intensity remains constant. Therefore, the current is not dependent on the angle of incidence.

- **Distance Between Cathode and Anode**: While increasing the distance can affect the number of electrons reaching the anode, if we assume sufficient potential is applied, the current remains largely unaffected by distance under normal conditions.

4. **Conclusion**:
Based on the analysis, the strength of the photoelectric current is directly proportional to the **intensity of the incident radiation**.

### Final Answer:
The strength of the photoelectric current is directly proportional to the **intensity of incident radiation**.

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