JEE Main · 2019 · 08 Apr 2019 · Shift 1 · EM Waves

WhatsApp Email

A plane electromagnetic wave travels in free space along the x -direction. The electric field component of the wave at a particular point of space and time is

E = 6 Vm^{- 1}

along y -direction. Its corresponding magnetic filed component, B would be:

(A) $2 \times 1 0^{- 8} T$ along z - direction✓ Correct
(B) $6 \times 1 0^{- 8} T$ along x -direction
(C) $6 \times 1 0^{- 8} T$ along z - direction
(D) $2 \times 1 0^{- 8} T$ along y -direction

Answer: (A)

Solution

An electromagnetic wave travels along

E \times B

, so with propagation along

\hat{i}

and

E

along

\hat{j}

, the magnetic field must point along

\hat{k}

to make

\hat{j} \times \hat{k} = \hat{i}

the direction of travel. Its magnitude is

B = \frac{E}{c} = \frac{6}{3 \times 1 0 ^{8}} = 2 \times 1 0^{- 8}

T, so the magnetic field component is

2 \times 1 0^{- 8}

T along the z-direction.

JEE Main · 2019 · 08 Apr 2019 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on EM Waves →

JEE Main · 2019 · 08 Apr 2019 · Shift 1 · EM Waves

Solution

More JEE Main questions on EM Waves