Question

Hii...

If length and number of turns becomes half for a solenoid then value of magnetic field becomes:-
1)twice
2)same
3)half
4)one fourth

need a proper ans with explanation ...
no spams!!

Answer 1

for a long solenoid the value of magnetic field is, B= uNi÷L
where , u is the permeability
N is the no. of turns
L is the length of solenoid.
i is the flowing current.

thus magnetic field proportional to ratio of (N÷L)
as here N and L both become half so there ratio remain same.
So the filed remain same .