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Wave Optics · Question 11

JEE Main 2026 (Online) 4th April Evening ShiftNumericalEasy📈 Topic in 45% papers+4
1

In a double slit experiment, when one of the slits is covered by a transparent mica sheet of refractive index 1.56, the central fringe shifts to the position of 7th bright fringe, obtained with both slits uncovered. If the light source wavelength is 450 nm, the thickness of mica sheet is 10-9 m. The value of is .

Answer

5625

Solution

The mica sheet adds an optical path ( -1)t; the central fringe shifts to the 7th bright fringe:

( -1)t=7

t= 7 450 10-91.56-1= 3150 10-90.56

t=5625 10-9 m

=5625

Answer: 5625

JEE Main 2026 (Online) 4th April Evening Shift

Keep practising — Wave Optics

2

In single slit diffraction pattern, the wavelength of light used is 628 nm and slit width is 0.2 mm, the angular width of central maximum is 10-2 degrees. The value of is .

JEE Main 2026 (Online) 2nd April Morning Shift
3

In a Young's double slit experiment, the intensity at some point on the screen is found to be 34 times of the maximum of the interference pattern. The path difference between the interfering waves at this point is x where is wavelength of the incident light. The value of x is .

JEE Main 2026 (Online) 2nd April Evening Shift
4

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are false
  2. Both Statement I and Statement II are true
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 28th January Morning Shift
5

A beam of light consisting of wavelengths 650 nm and 550 nm illuminates the Young's double slits with separation of 2 mm such that the interference fringes are formed on a screen, placed at a distance of 1.2 m from the slits. The least distance of a point from the central maximum, where the bright fringes due to both the wavelengths coincide, is 10-5 m.

JEE Main 2026 (Online) 28th January Evening Shift
6

An unpolarised light is incident at an interface of two dielectric media having refractive indices of 2 (incident medium) and 2 3 (refracted medium) respectively. To satisfy the condition that reflected and refracted rays are perpendicular to each other, the angle of incidence is

  1. 45
  2. 60
  3. 10
  4. 30
JEE Main 2026 (Online) 24th January Morning Shift
7

In the Young's double slit experiment the intensity produced by each one of the individual slits is Io. The distance between two slits is 2 mm. The distance of screen from slits is 10 m. The wavelength of light is 6000 . The intensity of light on the screen in front of one of the slits is

  1. Io2
  2. Io
  3. 2Io
  4. 4Io
JEE Main 2026 (Online) 24th January Evening Shift
8

In two separate Young's double-slit experimental set-ups and two monochromatic light sources of different wavelengths are used to get fringes of equal width. The ratios of the slits separations and that of the wavelengths of light used are 2 : 1 and 1 : 2 respectively. The corresponding ratio of the distances between the slits and the respective screens (D1/D2) is .

JEE Main 2026 (Online) 23rd January Morning Shift
9

When an unpolarized light falls at a particular angle on a glass plate (placed in air), it is observed that the reflected beam is linearly polarized. The angle of refracted beam with respect to the normal is . ( -1(1.52) = 57.7 , refractive indices of air and glass are 1.00 and 1.52, respectively.)

  1. 36.3
  2. 39.6
  3. 42.6
  4. 32.3
JEE Main 2026 (Online) 23rd January Evening Shift
10

Which of the following are true for a single slit diffraction?

  1. B, D only
  2. A, D only
  3. A, C, E only
  4. B, C only
JEE Main 2026 (Online) 22nd January Evening Shift
11

In a double slit experiment the distance between the slits is 0.1 cm and the screen is placed at 50 cm from the slits plane. When one slit is covered with a transparent sheet having thickness t and refractive index n (= 1.5), the central fringe shifts by 0.2 cm. The value of t is cm.

  1. 6.0 10-3
  2. 8 10-4
  3. 5.0 10-3
  4. 5.6 10-4
JEE Main 2026 (Online) 21st January Morning Shift

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