(A) : Working of a moving coil galvanometer is based on heating effect of current.
(R) : On heating, the coil starts to rotate in moving coil galvanometer because fo torque.

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is false

Answer

To solve the question regarding the working principle of a moving coil galvanometer, we will analyze both the assertion (A) and the reason (R) provided in the question.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "the working of a moving coil galvanometer is based on the heating effect of current."
- The heating effect of current refers to the phenomenon where electrical energy is converted into heat energy when current flows through a conductor due to its resistance. However, this is not the principle on which a moving coil galvanometer operates.

2. **Understanding the Reason (R)**:
- The reason states that "on heating, the coil starts to rotate in a moving coil galvanometer because of torque."
- In a moving coil galvanometer, the coil rotates due to the interaction between the magnetic field and the electric current flowing through the coil, not due to heating. The torque experienced by the coil is a result of the magnetic field acting on the current-carrying coil.

3. **Analyzing the Relationship between (A) and (R)**:
- The assertion (A) is incorrect because the working of a moving coil galvanometer is based on the magnetic effect of current, not the heating effect.
- The reason (R) is also incorrect because the rotation of the coil is not due to heating but due to the torque produced by the magnetic field acting on the current in the coil.

4. **Conclusion**:
- Since both the assertion and the reason are incorrect, the correct answer to the question is that both (A) and (R) are false.

### Final Answer:
Both assertion (A) and reason (R) are false.

---