In the right Figure there is a constant magnetic field in a rectangular region o
ID: 1649482 • Letter: I
Question
In the right Figure there is a constant magnetic field in a rectangular region of space. This field is directed perpendicularly into the page. Outside this region there is no magnetic field. A copper ring slides through the region, from position 1 to position 5. Which one of the following options correctly describes the induced current in the ring as it passes through positions 2, 3, and 4? (A) I2 clockwise I3 counterclockwise I4 counterclockwise. (B) I2 is counterclockwise I3 is clockwise I4 clockwise (C) I2 is a clockwise I3 - 0 A I4 is counterclockwise (D) I2 is counterclockwise I3 = 0 A I4 is clockwiseExplanation / Answer
In this we'll use two Laws:
Lenz's law: stating that if there is change in the magnetic flux through the closed loop then current is induced in the loop in such a way so as to oppose the cause due to which it is produced.
Right Hand Thumb Rule: stating that if thumb of right hand points in the direction of Magnetic Field then curls of the fingers will point in the direction of current.
Now for Position 2: Since "into the page" magnetic field is increasing then following Lenz's law, current should be induced in a way to decrease this increasing field or using Right Hand Thumb Rule, current should be induced in counterclockwise direction to have "out of the page" magnetic field.
For Position 3: Since "into the page" magnetic field is constant hence no current will be induced at this position.
For Position 4: Since "into the page" magnetic field is decreasing at this position then following Lenz's law, current should be induced in a way to increase this decreasing field or using Right Hand Thumb Rule, current should be induced in clockwise direction to have "into the page" magnetic field.
Hence correct option: D). I2 is counterclockwise, I3 is 0A, I4 is clockwise.