Which of the following statement is true in the context of photoelectic effect?

Options

A. The kinetic energy of ejected electron is independent of the intensity of a radiation.
B. The number of photoelectrons ejected depends upon the intensity of the incident radiation.
C. The kinetic energy of the emitted electrons depends on the frequency of the incident radiation
D. All of these

Explanation

To determine which statement is true in the context of the photoelectric effect, we can analyze each statement based on our understanding of the phenomenon. The photoelectric effect describes the emission of electrons from a material when it is exposed to light (or electromagnetic radiation).

### Step-by-Step Solution:

1. **Understanding the Photoelectric Effect**:
- The photoelectric effect occurs when light of sufficient frequency strikes a material and causes the emission of electrons. The energy of the incoming photons is critical in this process.

2. **Analyzing the Kinetic Energy of Ejected Electrons**:
- The kinetic energy (KE) of the emitted electrons is given by the equation:
\[ KE = h\nu - \phi \]
where \( h \) is Planck's constant, \( \nu \) is the frequency of the incident light, and \( \phi \) is the work function of the material.
- From this equation, we can see that the kinetic energy of the ejected electrons depends on the frequency of the incident radiation and not on its intensity.

3. **Examining the Intensity of Radiation**:
- The intensity of the incident radiation is related to the number of photons striking the surface per unit time. Higher intensity means more photons, which can lead to more electrons being emitted, but does not affect the kinetic energy of the emitted electrons.

4. **Evaluating the Statements**:
- **Statement 1**: The kinetic energy of the ejected electron is independent of the intensity of radiation.
- This statement is **true**.
- **Statement 2**: The number of electrons ejected depends upon the intensity of the incident radiations.
- This statement is **true**; higher intensity leads to more emitted electrons.
- **Statement 3**: The kinetic energy of emitted electrons depends on the frequency of incident radiation.
- This statement is **true**; higher frequency results in higher kinetic energy.
- **Statement 4**: All of these statements are true.
- Since all previous statements are true, this statement is also **true**.

5. **Conclusion**:
- Therefore, the correct answer to the question is **D: All of these statements are true**.