Question

When a D.M. is arranged in $tanA$ position, a short bar magnet produced a deflection of ${60}^o$. If the same magnet is set at the same distance in Tan B position, the deflection in the D.M. is :

• A. ${60}^o$
• B. ${30}^o$
• C. less than ${45}^o$
• D. greater than ${45}^o$

Answer 1

Answer: (C)

less than ${45}^o$

When a short magnet is placed at a distance d in tanA and then tanB positions and ${\theta }_A,{\theta }_B$ are the average deflection then
$\frac{tan{\theta }_A}{tan{\theta }_B}=2$
$tan{\theta }_B=\frac{tan{\theta }_A}{2}=\frac{\sqrt{3}}{2}<1$
Therefore ${\theta }_A<{45}^o$