Question

The needle of a deflection galvanometer shows a
deflection of 60° due to a short bar magnet at a
certain distance in tanA position. If the distance is
doubled, then the deflection will be
​

Answer 1

Answer:

sin−1(3–√8)

cos−1(3–√8)

tan−1(3–√8)

cot−1(3–√8)

Answer :

C

Solution :

For short bar magnet in tan A-position

μ04π2Md3=Htanθ…(i)

When distance is double, then new deflection θ′ is given by

μ04π2M(2d)3=Htanθ′…(ii)

∴tanθ′tanθ′=18⇒tanθ′=tanθ8=tan60∘8=3–√8

⇒θ′=tan−1(3–√8)

Explanation: