Question

A compass needle placed at a distance r from a short magnet in tanA position shows a deflection of 60⁰. If the distance is increased to r(3)^1/3, then the deflection of the compass needle is –

• A. 30⁰
• B. 60⁰ × (3)^1/3
• C. 60⁰ × (3)^2/3
• D. 60⁰ × (3)^3/3

Answer 1

Answer: (A)

30⁰

Answer 2

In tan A position $\frac { 2 \mathrm { kM } } { \mathrm { r } ^ { 3 } }$ = B_H tanθ

$\frac { \tan \theta _ { 2 } } { \tan \theta _ { 1 } }$ ⇒ θ₂ = 30⁰