The formula for magnetic field of a certain component is given by
where, = total number of turns, = current, = radius. The component is:
1
ring
2
solenoid
3
toroid
4
None of these
Official Solution
Correct Option: (3)
Concept:
Magnetic field inside a toroid is:
Step 1: Identify formula.
Given expression matches exactly with toroid field formula. Step 2: Conclusion.
02
PYQ 2021
medium
physicsID: met-2021
Two wires PQ and QR carry equal currents I as shown in figure. One end of both the wires extends to infinity . The magnitude of the magnetic field at O on the bisector of these two wires at a distance r from point Q is:
1
2
3
4
Official Solution
Correct Option: (4)
Concept:
Magnetic field due to a semi-infinite straight wire:
Step 1: Field due to each wire.
Each wire is semi-infinite, so for point O:
Similarly for second wire:
Step 2: Direction of fields.
Using right-hand rule, fields due to both wires are symmetric.
Resolve along bisector direction. Step 3: Resultant field.
