Question 157: 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

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