Answer:
B'=1.935 T
Explanation:
Given that
magnetic field ,B= 0.645 T
We know that magnetic filed in the solenoid is given as
[tex]B=\mu _0 n\ I [/tex]
I=Current
n=Number of turn per unit length
μ0 =magnetic permeability
Now when the current increased by 3 factors
I'=3 I
Then the magnetic filed
[tex]B'=\mu _0 n\ I'[/tex]
[tex]B'=\mu _0 n\ (3I)[/tex]
B'=3 B
That is why
B' = 3 x 0.645 T
B'=1.935 T
Therefore the new magnetic filed will be 1.935 T.