Electromagnetic Induction · Rotating Loops

Turn a loop through a magnetic half-plane and watch the current waveform

Each conducting loop rotates clockwise about the fixed point O. The uniform magnetic field exists only in the shaded half-plane x > 0. As the area of the loop inside that region changes, so does the magnetic flux — and Faraday's law turns that changing flux into an induced current.

Loop P · semicircle
The gold region is the part of the loop currently inside the magnetic field
Choose a conducting loop
Rotation speed 1.0×
P · Semicircular loop
The overlap area changes steadily during each half-turn, so the induced current stays constant before reversing direction.
Matched graphList-II (3)
Current shapeconstant, then reversed
Magnetic field Buniform and into the page for x > 0
Conducting looprotates clockwise about O
Area contributing to fluxthe loop-field overlap

How to read the animation

01 / OVERLAP

Only the shaded side counts

The field is present only for x > 0, so the flux is B times the part of the loop area that lies inside the shaded half-plane.

Φ = B · Aoverlap
02 / CHANGE

Flux change drives current

A steadily growing overlap gives a constant current. A fixed overlap gives zero current. A shrinking overlap reverses the sign.

i ∝ − dΦ/dt
03 / MATCH

Shape controls the graph

Different boundaries cross the y-axis at different times. That geometry creates the plateaus, gaps and reversals seen in List-II.

The correct match
P
semicircle
List-II (3)
Q
split loop
List-II (2)
R
60° sector
List-II (1)
S
balanced loop
List-II (4)

Therefore the correct option is (C): P→3, Q→2, R→1, S→4.