Physics Circle home Student Login

Home›Chapters›Electromagnetic Waves PYQs›Nature of EM Waves & Wave Equation›Question 6

JEE Main 2026 (2 Apr, Shift 1) · Nature of EM Waves & Wave Equation

Nature of EM Waves & Wave Equation question from JEE Main 2026 (2 Apr, Shift 1)

Q6JEE Main 2026 · 2 APR · SHIFT 1Medium

Nature of EM Waves & Wave Equation

An electromagnetic wave travelling in x-direction is described by field equation

Ey=300sin⁡ω(t−xc)E_y = 300 \sin \omega \left(t - \frac{x}{c}\right).

If the electron is restricted to move in y-direction only with speed of 1.5×1061.5 \times 10^{6} m/s then ratio of maximum electric and magnetic forces acting on the electron is ______.

Show answer and solution

Answer: (a)

  1. Electric force FE=eE0F_E = eE_0; B⃗\vec B is along zz with B0=E0/cB_0 = E_0/c, and v⃗⊥B⃗\vec v\perp\vec B, so FB=evB0F_B = evB_0.
  2. FEFB=E0vB0=cv\dfrac{F_E}{F_B} = \dfrac{E_0}{vB_0} = \dfrac{c}{v}
  3. 3×1081.5×106=200\dfrac{3\times10^{8}}{1.5\times10^{6}} = 200
  4. So the answer is (a) 200.
Report a mistake

More questions on Nature of EM Waves & Wave Equation