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Alternating Current

Question

A beam of light travelling along X-axis is described by the electric field E_v = 600 $\frac{V}{m}$ . sin $ω (t - \frac{x}{c})$ , the maximum magnetic force on a charge q = 2e, moving along Y-axis with the speed of 3 × 10⁸ m/s is

19.2 × 10^-17 N

1.92 × 10^-17

0.192

None of these

Solution

19.2 × 10^-17 N

Given, electric field

E_y = $600 \frac{v}{m}$ . sin $ω (t - \frac{x}{c})$ ......(i)

We know that

E = E₀ sinω $(t - \frac{x}{c})$ .........(ii)

On comparing Eqs. (i) and (ii), we get

E₀ = 600 V/m

and C = 3 × 10⁸ m/s

Maximum magnetic field

B₀ = $\frac{E_{0}}{C}$

= $\frac{600}{3 \times 10^{8}}$

B₀ = 2 × 10^-6 T

∴ F_m = q V B₀

= 2 ev B₀

= 2 × 1.6 × 10^-19 × 3 × 10⁸ × 2 × 10^-6

F_m = 19.2 × 10^-17