In Young’s double-slit arrangement, slits are separated by a gap of 0.5 mm, and the screen is placed at a distance of 0.5 m from them. The distance between the first and the third bright fringe formed when the slits are illuminated by monochromatic light of 5890 Å is:
a. 1178 × 10-6m
b. 1178 × 10-9m
c. 5890 × 10-7m
d. 1178× 10-12m
Answer:(a)
D = 0.5 m
d = 0.5 mm
λ = 5890Å
Distance between first and third bright fringe = 2β = 2λD/d
= 2 × 5890 × 10-10 × 0.5/(0.5×10-3)
= 1178 × 10-6 m
