JEE Main2013PhysicsMagnetic Properties of MatterActual
The earth's magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to 8 10²² Am ^2 , the value of earth's magnetic field near the equator is close to (radius of the earth .=6.4 10^6 ~m )
Options
- A0.6 Gauss
- B1.2 Gauss
- C1.8 Gauss
- D0.32 Gauss
Correct answer
A. 0.6 Gauss
Step-by-step solution
Given M=8 10²² Am ^2 d = R _ e =6.4 10^6 ~m Earth's magnetic field, B = ₀ 4 2 M d ^3 aligned &= 4 10⁻⁷ 4 2 8 10²² (6.4 10^6 )^3 & 0.6 Gauss aligned