Correct option is B
An
idler gear is a gear placed between the driving and driven gears in a gear train. It does not transmit power directly but is used to achieve specific mechanical objectives.
The primary purpose of an
idler gear in a gear train is to
change the direction of rotation of the driven gear without affecting the gear ratio. It is inserted between the driving and driven gears to achieve the required direction of rotation in applications where reversing the rotation is necessary.
The idler gear does not affect the speed or torque of the system; it simply transfers motion and adjusts the direction.
