JEE Main · 2023 · 13 Apr 2023 · Shift 2 · EM Waves

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In an electromagnetic wave, at an instant and at a particular position, the electric field is along the negative z -axis and magnetic field is along the positive x -axis. Then the direction of propagation of electromagnetic wave is:

(A)at $4 5^{\circ}$ angle from positive $y$ -axis
(B)negative $y$ -axis✓ Correct
(C)positive $z$ -axis
(D)positive $y$ -axis

Answer: (B)

Solution

The direction of propagation of an electromagnetic wave is given by

E \times B

. Here

E

is along

- \overset{z}{^}

and

B

is along

+ \overset{x}{^}

. Thus

E \times B = (- \overset{z}{^}) \times (\overset{x}{^}) = - \overset{y}{^}

, i.e., along the negative y-axis.

JEE Main · 2023 · 13 Apr 2023 · Shift 2 · Single correct option

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