Question

Which rule is used to know the direction of induced current in a circuit?
A. Galvanometer
B. Fleming’s right-hand rule
C. Right-hand thumb rule.
D. Fleming’s left-hand rule

Answer 1

Hint: When a conductor is in motion in a uniform magnetic field, there will be currently generated in the current-carrying conductor. This is the statement of Faraday’s law of induction. Then the direction of current induced in that current-carrying conductor is stated by Fleming’s right-hand rule.

Complete step by step solution:
(i) Faraday’s law of induction: When a current-carrying conductor is in uniform motion in a uniform magnetic field, there will be current induced in that current-carrying conductor.
(ii) Fleming’s right-hand rule: Fleming’s right-hand rule gives the direction of the current in the conductor which is moving in the uniform magnetic field.

The rule states that stretch the thumb, forefinger, and the middle finger of the right hand in a way that they are in the mutually perpendicular direction as shown in the figure. Then, the thumb points the direction of motion of the conductor, the forefinger points the direction of the uniform magnetic field from north pole to the south pole, and the middle finger points the direction of the induced or generated current within the conductor from the terminal of lower electric potential to the terminal of higher electric potential.

Hence, option (B) is correct.

Note:
There is a simple way to recall Fleming’s right-hand rule is the ‘FBI’. F stands for Force ( or the motion of conductor), $B$ stands for the magnetic field and $I$ is for induced current in the conductor. It is followed by counting the letters in ‘FBI’ as from the top of your hand, the thumb is for $F$, the forefinger is for magnetic field and the middle finger is for induced current.