The needle of a deflection galvanometer shows a deflection of 60o due to a short bar magnet at a certain distance in tan A position. If the distance is doubled, the deflection is

For short bar magnet in tan A-position, μ04π2Md3=BH tanθ   ........(i)When distance is doubled, then new deflection θ' is given by μ04π2M2d3=BH tanθ '  ........(ii)∴tan θ'tan θ=18⇒tan θ'=tan θ8=tan 60o8=38⇒θ'=tan-138