Ray Optics · JEE Main previous year questions

2012 5 questions

1. Q522012 · 26 May 2012 · Shift 1
   
   1. A.no light
   2. B.green and blue colours
   3. C.red and green colours
   4. D.red colour only
   Show answer

   Answer: D

2. Q532012 · 26 May 2012 · Shift 1

   A telescope of aperture $3\times 10^{-2}\mathrm{m}$ diameter is focused on a window at $80\mathrm{m}$ distance fitted with a wire mesh of spacing $2\times 10^{-3}\mathrm{m}$. Given: $\lambda =5.5\times 10^{-7}\mathrm{m}$, which of the following is true for observing the mesh through the telescope?

   1. A.Yes, it is possible with the same aperture size.
   2. B.Possible also with an aperture half the present diameter.
   3. C.No, it is not possible.
   4. D.Given data is not sufficient.
   Show answer

   Answer: A

3. Q512012 · 12 May 2012 · Shift 1

   We wish to make a microscope with the help of two positive lenses both with a focal length of $20\mathrm{mm}$ each and the object is positioned $25\mathrm{mm}$ from the objective lens. How far apart the lenses should be so that the final image is formed at infinity?

   1. A.$20\mathrm{mm}$
   2. B.$100\mathrm{mm}$
   3. C.$120\mathrm{mm}$
   4. D.$80\mathrm{mm}$
   Show answer

   Answer: C

4. Q582012 · 12 May 2012 · Shift 1

   This question has Statement 1 and Statement 2. Of the four choices given after the Statements, choose the one that best describes the two Statements. Statement 1: Bats emitting ultrasonic waves can detect the location of a prey by hearing the waves reflected from it. Statement 2: When the source and the detector are moving, the frequency of reflected waves is changed.

   1. A.Statement 1 is false, Statement 2 is true.
   2. B.Statement 1 is true, Statement 2 is false.
   3. C.Statement 1 is true, Statement 2 is true, Statement 2 is not the correct explanation of Statement 1.
   4. D.Statement 1 is true, Statement 2 is true, Statement 2 is the correct explanation of Statement 1.
   Show answer

   Answer: C

5. Q532012 · 7 May 2012 · Shift 1

   Which of the following processes play a part in the formation of a rainbow? (i) Refraction (ii) Total internal reflection (iii) Dispersion (iv) Interference

   1. A.(i), (ii) and (iii)
   2. B.(i) and (ii)
   3. C.(i), (ii) and (iv)
   4. D.(iii) and (iv)
   Show answer

   Answer: A