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JEE Main 20244 AprilMorning Shift
Exam
JEE Main
Year
2024
Date
4 April
Shift
Morning Shift
Subject
Physics
Chapter
Electromagnetic Waves

JEE Main 2024 · 4 April · Morning Shift · Physics · Electromagnetic Waves

The electric field in an electromagnetic wave is given by E = i 40...

The electric field in an electromagnetic wave is given by E→=i^40cos⁡ω(t−z/c)NC−1\overrightarrow{\mathrm{E}}=\hat{i} 40 \cos \omega(\mathrm{t}-z / \mathrm{c}) \mathrm{NC}^{-1}. The magnetic field induction of this wave is (in SI unit) :

Options

  1. AB→=k^40Ccos⁡ω(t−z/c)\overrightarrow{\mathrm{B}}=\hat{k} \frac{40}{\mathrm{C}} \cos \omega(\mathrm{t}-z / \mathrm{c})
  2. BB⃗=j^40cos⁡ω(t−z/c)\vec{B}=\hat{j} 40 \cos \omega(t-z / c)
  3. CB→=i^40Ccos⁡ω(t−z/c)\overrightarrow{\mathrm{B}}=\hat{i} \frac{40}{\mathrm{C}} \cos \omega(\mathrm{t}-z / \mathrm{c})
  4. DB→=j^40Ccos⁡ω(t−z/c)\overrightarrow{\mathrm{B}}=\hat{j} \frac{40}{\mathrm{C}} \cos \omega(\mathrm{t}-z / \mathrm{c})

Correct answer

D. B→=j^40Ccos⁡ω(t−z/c)\overrightarrow{\mathrm{B}}=\hat{j} \frac{40}{\mathrm{C}} \cos \omega(\mathrm{t}-z / \mathrm{c})

Step-by-step solution

\overrightarrow{\mathrm{E}}=\hat{\mathrm{i}} 40 \cos \omega\left(\mathrm{t}-\frac{\mathrm{z}}{\mathrm{c}}\right)E→\overrightarrow{\mathrm{E}} is along +x+\mathrm{x} direction v→\overrightarrow{\mathrm{v}} is along +z+\mathrm{z} direction So direction of B⃗\vec{B} will be along +y and magnitude of BB will be Ec\frac{E}{c} So answer is 40ccos⁡ω(t−zc)j^\frac{40}{c} \cos \omega\left(t-\frac{z}{c}\right) \hat{j}
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