Question

Magnetic field is select one: a. None of the above b. Directly proportional to distance c. Direct proportional to current d. Indirectly prortional to charge

Answer 1

C IS THE ANSWER

if an alternating current is flowing, a magnetic field around the conductor will be produced, that is in phase with the alternating current.

Answer 2

answer : option (c)

according to Biot-Savart’s Law, magnetic field is directly proportional to current, elementary length of conducting wire , sine of angle made between direction of elementary length and point of observation and inversely proportional to separation between elementary length of conductor to point of observation.

e.g., $B\propto\frac{I.dlsin\theta}{r^2}$

where I is current through wire, dl is elementary length of wire , r is the separation between elementary length to point of observation and $\theta$ is angle made between direction of elementary length and point of observation.

hence, it is clear that magnetic field is directly proportional to current.

therefore, option (c) is correct choice.