Question

In vacuum, electromagnetic waves travel at the speed of

• A. $3\times {10}^{8}m/s$
• B. $3\times {10}^{6}m/s$
• C. $3\times {10}^{-8}m/s$
• D. $3\times {10}^{18}m/s$

Answer 1

The correct option is A $3\times {10}^{8}m/s$

In vacuum, electromagnetic waves travel at speed of $3\times {10}^8$ m/s.

C = speed of EM waves

C = $\frac{1}{\sqrt{{\mu }_0{\epsilon }_0}}$

${\mu }_0$ = permaebility of free space

${\epsilon }_0$ = permittivity of free space

putting the value of ${\mu }_0$ and ${\epsilon }_0$ we get value of C approximately $3\times {10}^8$ m/s.

${\mu }_0$ = $1.257\times {10}^{-6}$ Henry/meter

${\epsilon }_0$ = $8.85\times {10}^{-12}$ Farad/meter