Question 5: EM waves

Question

A plane electromagnetic wave with frequency 40 MHz travels in free space. At a particular point in space and time, the magnetic field is $2 	imes 10^{-8} T$. What will be the electric field at this point?

Accepted Answer

The electric and magnetic fields in a free-space plane wave are related by
$$E = c\,B$$
where $c = 3	imes10^8m\ m/s$.  Plugging in $B = 2	imes10^{-8}m\ T$,
$$E = (3	imes10^8)(2	imes10^{-8}) = 6\ m V/m\,. $$
So the correct choice is Option B: 6 V/m.

Answer

$16 \mathrm{Vm}^{-1}$

Answer

$6 \mathrm{Vm}^{-1}$

Answer

$8 \mathrm{Vm}^{-1}$

Answer

$18 \mathrm{Vm}^{-1}$

EM waves

A plane electromagnetic wave with frequency 40 MHz travels in free space. At a particular point in space and time, the magnetic field is 2 \times 10^{-8} T. What will be the electric field at this point?

Choose the correct answer: