Question

The velocity of an electromagnetic wave in vacuum can be changed by changing

• A. frequency
• B. amplitude
• C. wavelength
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

In free space speed of electromagnetic wave
$c=\frac{1}{\sqrt{\mu_{0} \varepsilon_{0}}}=\frac{E_{0}}{B_{0}}$
$=3 \times 10^{8} ms ^{-1}$
Thus, the value of electromagnetic wave is constant and cannot be changed by changing any of the given factors.