Assertion : Electron microscope has more resolving power than optical microscope.
Reason : We can control the energy of electron.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

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

### Step 1: Understanding the Assertion
The assertion states that "Electron microscope has more resolving power than optical microscope."

**Explanation**:
- Resolving power refers to the ability of an optical instrument to distinguish between two closely spaced objects.
- The resolving power is inversely proportional to the wavelength of the radiation used. This means that the shorter the wavelength, the higher the resolving power.

### Step 2: Understanding the Reason
The reason states that "We can control the energy of electron."

**Explanation**:
- While it is true that we can control the energy of electrons in an electron microscope, this does not directly explain why electron microscopes have higher resolving power than optical microscopes.
- The key factor that contributes to the higher resolving power of electron microscopes is the much shorter wavelength of electron beams compared to visible light used in optical microscopes.

### Step 3: Comparing Wavelengths
- The wavelength of electron beams is approximately \(10^{-5}\) times shorter than that of visible light.
- Since resolving power is inversely proportional to wavelength, this significant difference in wavelength leads to a much higher resolving power for electron microscopes.

### Step 4: Conclusion
- The assertion is true: Electron microscopes do have more resolving power than optical microscopes.
- The reason is also true: We can control the energy of electrons.
- However, the reason does not correctly explain the assertion. The higher resolving power is primarily due to the shorter wavelength of electrons, not just the ability to control their energy.

### Final Answer
Thus, the correct conclusion is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion. Therefore, the answer is option B: "Assertion and reason are true, but reason is not the correct explanation of assertion."

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