Electromagnetic Waves · JEE Main previous year questions

2023 5 questions

1. Q452023 · 13 Apr 2023 · Shift 2

   Given below are two statements: Statement I : Out of microwaves, infrared rays and ultraviolet rays, ultraviolet rays are the most effective for the emission of electrons from a metallic surface. Statement II : Above the threshold frequency, the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light. In the light of above statements, choose the correct answer form the options given below

   1. A.Both Statement I and Statement II are true
   2. B.Statement I is true but statement II is false
   3. C.Statement I is false but statement II is true
   4. D.Both Statement I and Statement II are false
   Show answer

   Answer: B

2. Q342023 · 12 Apr 2023 · Shift 1

   Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology. Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar) In the light of given statements, choose the correct answer from the options given below.

   1. A.Both A and R are true but R is NOT the correct explanation of A
   2. B.A is true but R is false
   3. C.Both A and R are true and R is the correct explanation of A
   4. D.A is false but R is true
   Show answer

   Answer: D

3. Q322023 · 11 Apr 2023 · Shift 2

   A plane electromagnetic wave of frequency $20\text{ MHz}$ propagates in free space along $x$-direction. At a particular space and time, $\vec{\mathrm{E}}=6.6\hat{j}\text{ V/m}$. What is $\vec{\mathrm{B}}$ at this point?

   1. A.$-2.2\times 10^{-8}\hat{i}\text{T}$
   2. B.$2.2\times 10^{-8}\hat{i}\text{T}$
   3. C.$2.2\times 10^{-8}\hat{k}\text{T}$
   4. D.$-2.2\times 10^{-8}\hat{k}\text{T}$
   Show answer

   Answer: C

4. Q452023 · 6 Apr 2023 · Shift 1

   For the plane electromagnetic wave given by $E=E_0\sin (\omega t-kx)$ and $B=B_0\sin (\omega t-kx)$, the ratio of average electric energy density to average magnetic energy density is

   1. A.1
   2. B.4
   3. C.2
   4. D.1/2
   Show answer

   Answer: A

5. Q362023 · 31 Jan 2023 · Shift 2

   Match List I with List II | LIST I | LIST II | | :--- | :--- | | A. Microwaves | I. Physiotherapy | | B. UV rays | II. Treatment of cancer | | C. Infra-red light | III. Lasik eye surgery | | D. X-ray | IV. Aircraft navigation | Choose the correct answer from the options given below:

   1. A.A - IV, B - III, C - I, D - II
   2. B.A - II, B - IV, C - III, D - I
   3. C.A - III, B - II, C - I, D - IV
   4. D.A - IV, B - I, C - II, D - III
   Show answer

   Answer: A