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NEET PHYSICSELECTROMAGNETIC WAVESEasy

Question

The magnetic field in a plane electromagnetic wave is given by: By=2×107sin(π×103x+3π×1011t) TB_y = 2 \times 10^{-7} \sin(\pi \times 10^3x + 3\pi \times 10^{11}t) \text{ T}. The wavelength is:

A

π×103 m\pi \times 10^3 \text{ m}

B

2×103 m2 \times 10^{-3} \text{ m}

C

2×103 m2 \times 10^3 \text{ m}

D

π×103 m\pi \times 10^{-3} \text{ m}

Step-by-Step Solution

The standard equation for the magnetic field of an electromagnetic wave travelling in the x-direction is given by: By=B0sin(kx+ωt)B_y = B_0 \sin(kx + \omega t) where kk is the propagation constant (or wave number) and ω\omega is the angular frequency.

1. Identify kk from the given equation: Comparing the given equation By=2×107sin(π×103x+3π×1011t)B_y = 2 \times 10^{-7} \sin(\pi \times 10^3x + 3\pi \times 10^{11}t) with the standard form, the coefficient of xx is kk: k=π×103 rad/mk = \pi \times 10^3 \text{ rad/m}

2. Calculate Wavelength (λ\lambda): The relationship between wavelength and propagation constant is: k=2πλk = \frac{2\pi}{\lambda} λ=2πk\lambda = \frac{2\pi}{k}

Substituting the value of kk: λ=2ππ×103\lambda = \frac{2\pi}{\pi \times 10^3} λ=2×103 m\lambda = 2 \times 10^{-3} \text{ m}

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from ELECTROMAGNETIC WAVES. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSELECTROMAGNETIC WAVESmagneticelectromagneticwavelength

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