Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEETPhysicsElectromagnetic Waves

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For an electromagnetic wave propagating in a non-magnetic medium with relative permittivity _r = 4 , if the electric field amplitude is E₀ , the corresponding magnetic field amplitude is B₀ = E₀ 2c (where c is the speed of light in vacuum). Reason (R): The speed of an electromagnetic wave in a medi

Options

  1. ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
  2. BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
  3. CAssertion (A) is true but Reason (R) is false
  4. DAssertion (A) is false but Reason (R) is true

Correct answer

D. Assertion (A) is false but Reason (R) is true

Step-by-step solution

The speed of an electromagnetic wave in a medium is given by v = c _r _r . For a non-magnetic medium, the relative permeability _r = 1 . Given _r = 4 , the speed of the wave is v = c 1 4 = c 2 . The amplitudes of the electric and magnetic fields are related by E₀ = v B₀ . Substituting the value of v , we get E₀ = ( c 2 ) B₀ , which gives B₀ = 2E₀ c . The Assertion incorrectly states that B₀ = E₀ 2c . The Reason correctly states the standard formulas for wave speed and the amplitude relation. Therefore, Assertion (A

Practice Electromagnetic Waves on Quantrex Academy →

More from Electromagnetic Waves

A parallel-plate capacitor of 50 F contains a dielectric slab of constant ( k ) with the same dimensions. If a time-varying potential difference is applied at a rate of 50 V/s . Wh 2026An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant, _r=9 , has the electric field, E_x=E₀ (kz-2 10^6 t) Vm ⁻¹ where E₀ is the amplitude 2026Match List I with List II : List I (Electromagnetic wave) List II (Production) A. Microwave I. Electrons in atoms emit light when they move from a higher energy level to a lower en 2026The following table presents the part of the electromagnetic spectrum and their corresponding major applications. Part of the electromagnetic spectrum Applications P. Microwave I. 2026A parallel plate capacitor made of circular plates is being charged such that the surface charge density on its plates is increasing at a constant rate with time. The magnetic fiel 2025The electric field in a plane electromagnetic wave is given by E_z=60 (5 x +1.5 10^9 t ) V / m . Then expression for the corresponding magnetic field is (here subscripts denote the 2025A parallel plate capacitor is charged by connecting it to a battery through a resistor. If I is the current in the circuit, then in the gap between the plates: 2024The electromagnetic radiation which has the smallest wavelength are 2024 Full Electromagnetic Waves list All NEET PYQs