A: The power output of a practical transformer is always smaller than the power input.
R: A transformer works on the principle of mutual induction.

Options

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

Answer

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

### Step 1: Understanding the Assertion (A)
The assertion states that "The power output of a practical transformer is always smaller than the power input."

- **Explanation**: In a practical transformer, there are various losses that occur during the transformation of electrical energy from the primary coil to the secondary coil. These losses include:
- **Copper losses**: Due to the resistance of the wire in the coils.
- **Hysteresis losses**: Due to the magnetization and demagnetization of the core material.
- **Eddy current losses**: Caused by circulating currents induced in the core.

As a result of these losses, the power output (P_out) is indeed less than the power input (P_in). Thus, the assertion is **true**.

### Step 2: Understanding the Reason (R)
The reason states that "A transformer works on the principle of mutual induction."

- **Explanation**: A transformer operates based on the principle of mutual induction, which is the phenomenon where a change in current in one coil induces a voltage in another nearby coil. This principle is fundamental to the operation of transformers, allowing them to transfer energy from the primary to the secondary coil.

While the reason is correct, it does not explain why the power output is less than the power input. The losses mentioned in the assertion are not directly related to the principle of mutual induction.

### Conclusion
- The assertion (A) is true.
- The reason (R) is true, but it does not correctly explain the assertion.

Thus, the final answer is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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