Question

If the amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is \( 270 \) nT, the amplitude of the electric field part of the wave is:

• A. \( 90 \, \text{NC}^{-1} \)
• B. \( 81 \, \text{NC}^{-1} \)
• C. \( 9 \, \text{NC}^{-1} \)
• D. \( 30 \, \text{NC}^{-1} \)

Hint:

The amplitudes of electric and magnetic fields in an EM wave are related by \( E_0 = c B_0 \).

Answer 1

The Correct Option is B

The relation between electric field amplitude \( E_0 \) and magnetic field amplitude \( B_0 \) in an electromagnetic wave is: \[ E_0 = c B_0 \] where \( c = 3 \times 10^8 \) m/s and \( B_0 = 270 \times 10^{-9} \) T. \[ E_0 = (3 \times 10^8) \times (270 \times 10^{-9}) \] \[ E_0 = 81 \, \text{NC}^{-1} \]