Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: An electric fan continues to rotate for some time after the current is switched off.
Reason R: Fan continues to rotate due to inertia of motion.
In the light of above statements, choose the most appropriate answer from the options given below.

The assertion states that an electric fan continues to rotate for some time after the current is switched off, and this is correct because when the current to an electric fan is switched off, the fan does not stop immediately but continues to rotate and gradually slows down over several seconds, a commonly observed phenomenon. According to Newton’s First Law of Motion (the Law of Inertia), an object in motion continues in its state of motion unless acted upon by an external unbalanced force, and for rotational motion the analogous principle states that a rotating body continues to rotate unless acted upon by an external torque. The fan blades, motor rotor, and other rotating parts have mass and therefore possess rotational inertia (moment of inertia $$I$$). When the current is switched off, there is no longer a driving torque from the motor; however, the fan has angular momentum given by $$L = I\omega$$ where $$I$$ is the moment of inertia of the rotating parts and $$\omega$$ is the angular velocity. This angular momentum cannot vanish instantaneously, so the fan gradually decelerates due to frictional forces (air resistance and bearing friction) which provide a retarding torque $$\tau_{friction}$$, resulting in an angular deceleration $$\alpha = \frac{\tau_{friction}}{I}$$. Since the frictional torque is relatively small compared to the moment of inertia, it takes considerable time for the fan to come to rest.

The reason suggests that the fan continues to rotate due to inertia of motion, which is correct since it identifies that the fan’s continued rotation is due to rotational inertia, representing a direct application of Newton’s First Law extended to rotational motion, and thus the reason explains the assertion because the rotating fan tends to maintain its state of rotation and only external torques (friction, air resistance) can bring it to rest.

The correct answer is Option 3: Both A and R are correct and R is the correct explanation of A.