NEETPhysicsElectromagnetic Waves
The magnetic field of an electromagnetic wave travelling in a lossless, non-magnetic dielectric medium (dielectric constant _r = 4 ) is given by: B_z = 2 10⁻⁸ (1.5 10^8 t + x) T. Match the wave parameters in List-I with their corresponding values in List-II. List-I List-II (A) Speed of the wave in the medium (in m/s) (I) 3 (B) Wavelength of the wave (in m) (II) +x (C) Amplitude of the electric field (in V/m) (III) 1.
Options
- A(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
- B(A)-(III), (B)-(I), (C)-(IV), (D)-(V)
- C(A)-(III), (B)-(IV), (C)-(I), (D)-(V)
- D(A)-(IV), (B)-(III), (C)-(I), (D)-(II)
Correct answer
C. (A)-(III), (B)-(IV), (C)-(I), (D)-(V)
Step-by-step solution
The speed of the wave in the medium is v = c _r = 3 10^8 4 = 1.5 10^8 m/s. (Matches A-III) From the given equation, the wave vector k = rad/m. The wavelength is = 2 k = 2 = 2 m. (Matches B-IV) The amplitude of the electric field is E₀ = vB₀ = (1.5 10^8) (2 10⁻⁸) = 3 V/m. (Matches C-I) The phase of the wave is (1.5 10^8 t + x) . The positive sign between the time and space terms indicates that the wave is propagating in the -x direction. (Matches D-V) Thus, the correct matching is (A)-(III), (B)-(IV), (C)-(I), (D)-(