Question 148: Magnetism and Matter

Question

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of magnetic field will be equal to

Accepted Answer

$$B = {\mu _0}ni$$
Now $$i 	o 2i$$
And $$n 	o {n \over 2}$$
$$B' = {\mu _0}{n \over 2} 	imes 2i = {\mu _0}ni = B$$

Answer

B

Answer

2B

Answer

4B

Answer

$${B \over 2}$$

Magnetism and Matter

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of magnetic field will be equal to

Choose the correct answer: