Question

The ratio of the magnitudes of the electric field and \( 10^8 \) times the magnetic field of a plane electromagnetic wave is:

• A. \( 1 : 3 \)
• B. \( 3 : 1 \)
• C. \( 1 : 1 \)
• D. \( 1 : \sqrt{5} \)

Hint:

For plane electromagnetic waves, the electric and magnetic fields maintain the ratio: \[ E = c B \] where \( c \) is the speed of light.

Answer 1

The Correct Option is C

Step 1: Electromagnetic Wave Relationship In an electromagnetic wave: \[ E = c B \] where: - \( E \) = electric field magnitude, - \( B \) = magnetic field magnitude, - \( c \) = speed of light (\( 3 \times 10^8 \) m/s). Step 2: Given Condition The problem states that the magnetic field is scaled by \( 10^8 \): \[ E : (10^8 B) \] Since \( E = c B \), we substitute: \[ c B : (10^8 B) \] \[ (3 \times 10^8 B) : (10^8 B) \] Dividing: \[ 3 : 1 \] Conclusion Thus, the correct answer is: \[ 1 : 1 \]