12th Class Physics Magnetism Question Bank MCQs - Moving Charges and Magnetism

A straight conductor carries a current from south to north. Point P and Q lie to the east and west of it at the same distance. The magnetic field at P is

A) equal to magnetic field at Q.

B) smaller than the magnetic field at Q.

C) greater than the magnetic field at Q.

D) cannot be predicted unless the value if I is known.

Correct Answer: A

Solution :

Option [a] is correct.

Explanation: \[\operatorname{B}\propto I,\operatorname{B}\propto 1/r\]

So, if I and r remains constant, then magnetic field at P = Magnetic field at Q.