NEET Physics Youngs Double Slit Experiment MCQs Set 01

a) separation of slits

b) width of slits

c) wavelength of light used

d) distance between slits and screen

Answer: separation of slits

Question: If Young’s double slit experiment is performed in water keeping the rest of the set-up same, the fringes will

a) decrease in width

b) not be formed

c) increase in width

d) remain unchanged

Answer: decrease in width

Question:  In Young’s double slit experiment, one slit is covered with red filter and another slit is covered by green filter, then interference pattern will be

a) invisible

b) green

c) red

d) yellow

Answer: invisible

Question:  In Young's double slit experiment with sodium vapour lamp of wavelength 589 nm and the slits 0.589 mm apart, the half angular width of the central maximum is

a) sin^–1 (0.001)

b) sin^–1 (0.01)

c) None of these

d) sin^–1 (0.0001)

Answer: sin^–1 (0.001)

Question:  The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young’s double-slit experiment is

a) five

b) infinite

c) zero

d) three

Answer: five

Question:  In the Young’s Double slit experiment, when we place a converging lens after the slits and place the screen at the focus of the lens, it

a) introduces an extra fringe in the diffraction pattern

b) introduces an extra phase difference in the parallel beam.

c) introduces no path difference in the parallel beam

d) introduces an extra path difference in the parallel beam

Answer:  introduces an extra fringe in the diffraction pattern

 More Questions............................................

Question:  In Young’s experiment, two coherent sources are placed 0.90 mm apart and fringe are observed one metre away. If it produces second dark fringe at a distance of 1 mm from central fringe, the wavelength of monochromatic light used would be

a) 6 × 10^–5 cm

b) 10 × 10^–4 cm

c) 60 × 10^–4 cm

d) Nonwe of these

Answer:  6 × 10^–5 cm

Question: Distance between screen and source is decreased by 25%. Then the percentage change in fringe width is

a) 25%

b) 75%

c) 31%

d) 20%

Answer: 25%

Question:  Monochromatic light of wavelength 400 nm and 560 nm are incident simultaneously and normally on double slits apparatus whose slits separation is 0.1 mm and screen distance is 1m. Distance between areas of total darkness will be

a) 28 mm

b) 14 mm

c) 5.6 mm

d) 4 mm

Answer: 28 mm

Question:  In a Young's double slit experiment, the separation of the two slits is doubled. To keep the same spacing of fringes, the distance D of the screen from the slits should be made

a) 2D

b) 4D

c) 3D

d) 5D

Answer: 2D

Question:  In Young's double slit experiment, the fringes are displaced by a distance x when a glass plate of refractive index 1.5 is introduced in the path of one of the beams. When this plate is replaced by another plate of the same thickness, the shift of fringes is (3/2) x. The refractive index of the second plate is

a) 1.75

b) 1.50

c) 1.25

d) 1.00

Answer: 1.75

Question: Light of wavelength 6.5 × 10^–7 m is made incident on two slits 1 mm apart. The distance between third dark fringe and fifth bright fringe on a screen distant 1 m from the slits will be

a) 1.625 mm

b) 0.325 mm

c) 0.65 mm

d) 3.25 mm

Answer:  1.625 mm

Question:  In Young’s double slit expt. the distance between two sources is 0.1 mm. The distance of the screen from the source is 20 cm. Wavelength of light used is 5460 Å. The angular position of the first dark fringe is

a) 0.16º

b) 0.20º

c) 0.32º

d) 0.08º

Answer:  0.16º