Question

A radio transmitter transmits at $830kHz$. At a certain distance from the transmitter magnetic field has amplitude $4.82\times {10}^{-11}T$. Find the electric field and wavelength.

• A. $14.46\times {10}^{-3}N{C}^{-1},35m$
• B. $14.46\times {10}^{-3}N{C}^{-1},361.4m$
• C. $1.45\times {10}^{-3}N{C}^{-1},35m$
• D. none of these

Answer 1

The correct option is B $14.46\times {10}^{-3}N{C}^{-1},361.4m$

Using $v=\nu \lambda$ where $v$ is the speed of EM wave.

As $v=c=3\times {10}^{8}m/s$

$⟹3\times {10}^8=830\times {10}^3\lambda$

$⟹\lambda =361.4m$

Using $E=Bv=4.82\times {10}^{-11}\times 3\times {10}^8$

$⟹E=14.46\times {10}^{-3}N{C}^{-1}$