Verified Solution • 2025–26 Session moderate

QJEEM23Ph1362: JEE Main 2023 Physics - Class 12 JEEM23Ph1362 Solution: An electromagnetic wave is transporting energy in the negative…

An electromagnetic wave is transporting energy in the negative zz direction. At a certain point and certain time the direction of electric field of the wave is along positive yy direction. What will be the direction of the magnetic field of the wave at that point and instant?

Multiple Choice Options

  • A Negative direction of yy
  • B Positive direction of zz
  • C Positive direction of xx
  • D Negative direction xx

Step-by-Step Verified Solution

As, poynting vector

S→=E→×H→\overrightarrow{\mathrm{S}}=\overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{H}}

Given energy transport == negative z\mathrm{z} direction

Electric field == positive y\mathrm{y} direction

(−k^)=(+j^)×[i^](-\hat{\mathrm{k}})=(+\hat{\mathrm{j}}) \times[\hat{\mathrm{i}}]

Hence according to vector cross product magnetic field should be positive x\mathrm{x} direction.

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