Question

The ratio of the magnitudes of electric field to the magnetic field of an electromagnetic wave is of the order of

• A. 10⁸ ms^-1
• B. 10^-5 ms^-1
• C. 10⁵ ms^-1
• D. 10^-8 ms^-1

Answer 1

The Correct Option is A

Concept: 

For an electromagnetic wave, the ratio of the magnitudes of electric field (\( E \)) and magnetic field (\( B \)) is equal to the speed of light (\( c \)):

\[ \frac{E}{B} = c \]

Calculation:

The speed of electromagnetic waves (speed of light) in vacuum is approximately:

\[ c = 3 \times 10^{8}\,ms^{-1} \]

Given options are approximate orders of magnitude. The correct closest magnitude from the given choices is:

\[ 10^{8}\,ms^{-1} \]

Final Conclusion:
The ratio of electric field to magnetic field for electromagnetic waves is of the order \( 10^{8}\,ms^{-1} \).