An electromagnetic wave travelling in -direction is described by field equation . If the electron is restricted to move in

Question

An electromagnetic wave travelling in $x$ -direction is described by field equation $E_{y} = 300 \sin ω (t - \frac{x}{c})$ .

If the electron is restricted to move in $y$ -direction only with speed of $1.5 \times 10^{6} m / s$ then ratio of maximum electric and magnetic forces acting on the electron is ______. [2026]

Smart Achievers · Accepted Answer

(1)

$E_{y} = 300 \sin ω (t - \frac{x}{v})$

$F_{M} = q v B$ $. . . (i)$

$F_{e} = q E$ $. . . (i i)$

$\frac{F_{e}}{F_{M}} = \frac{q E}{q v B} = \frac{E}{v B} = \frac{c}{v} = \frac{3 \times 10^{8}}{1.5 \times 10^{6}} = 200$

Solution

1 200

2 150

3 400

4 300

Ans.
(1)

$E_{y} = 300 \sin ω (t - \frac{x}{v})$

$F_{M} = q v B$ $. . . (i)$

$F_{e} = q E$ $. . . (i i)$

$\frac{F_{e}}{F_{M}} = \frac{q E}{q v B} = \frac{E}{v B} = \frac{c}{v} = \frac{3 \times 10^{8}}{1.5 \times 10^{6}} = 200$

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