Assertion: we can increases the saturation current in photoelectric experiment without increasing the intensity of light.
Reason: Instensity can be increased by increasing the frequency of incident photons.

Options

A. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.
B. If both Assertion and Reason or true but Reason is not the correct explanation of Assertion.
C. If Assertion is true, but the Reason is false.
D. If Assertion is false but the Reason is true.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that we can increase the saturation current in a photoelectric experiment without increasing the intensity of light.

### Step 2: Define Saturation Current
Saturation current in the context of the photoelectric effect refers to the maximum current that can be achieved when all emitted photoelectrons are collected. This current is directly proportional to the number of photoelectrons emitted, which in turn is related to the number of incident photons.

### Step 3: Relate Intensity and Frequency
Intensity (I) of light is defined as the energy per unit area per unit time. It can be expressed as:
\[ I = N \cdot hf \]
where:
- \( N \) is the number of photons incident per unit area per second,
- \( h \) is Planck's constant,
- \( f \) is the frequency of the incident light.

### Step 4: Analyze the Assertion
If we keep the intensity constant but decrease the frequency \( f \), the number of photons \( N \) must increase to maintain the same intensity since:
\[ N = \frac{I}{hf} \]
Thus, by decreasing the frequency, we can increase the number of photons \( N \), which in turn increases the saturation current. Therefore, the assertion is true.

### Step 5: Understand the Reason
The reason states that intensity can be increased by increasing the frequency of incident photons. This is also true, as increasing frequency while keeping the number of photons constant will increase the energy of each photon, thus increasing the overall intensity.

### Step 6: Evaluate the Relationship
While both the assertion and the reason are true, the reason does not explain the assertion. The assertion is about increasing saturation current without increasing intensity, while the reason discusses how to increase intensity.

### Final Conclusion
Based on the analysis:
- The assertion is true.
- The reason is true but does not explain the assertion.

Thus, the correct answer is that the assertion is true, and the reason is also true but does not explain the assertion.