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Friday, 9 October

JEE Main 2026 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 4 April 2026, Shift 2, Physics Q40

Question 40 of 75 in this shift, Physics question 15 of 25, Section A.

A magnetic field vector in an electromagnetic wave is represented by B⃗=B0sin⁡(2πvt−2πxλ) j^\vec B=B_0\sin\left(2\pi vt-\frac{2\pi x}{\lambda}\right)\,\hat j. Its associated electric field vector is ________.
  1. (1)E⃗=−vλB0sin⁡(2πvt−2πxλ) k^\vec E=-v\lambda B_0\sin\left(2\pi vt-\frac{2\pi x}{\lambda}\right)\,\hat kOfficial answer
  2. (2)E⃗=−vλB0sin⁡(2πvt−2πxλ) i^\vec E=-v\lambda B_0\sin\left(2\pi vt-\frac{2\pi x}{\lambda}\right)\,\hat i
  3. (3)E⃗=vλB0sin⁡(2πvt−2πxλ) k^\vec E=v\lambda B_0\sin\left(2\pi vt-\frac{2\pi x}{\lambda}\right)\,\hat k
  4. (4)E⃗=vλB0sin⁡(2πvt−2πxλ) i^\vec E=v\lambda B_0\sin\left(2\pi vt-\frac{2\pi x}{\lambda}\right)\,\hat i

Official answer

Option 1

NTA final key.

Chapter
Electromagnetic Waves
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.