COMEDK2014PhysicsWave Optics
A screen is placed 2 ~m away from a narrow slit. It the first minimum lies 5 mm from either side of the central maxima, when plane waves of wavelength 5 10⁻⁷ ~m are used, the slit width is
Options
- A4.8 10⁻⁴ ~m
- B2 10⁻⁴ ~m
- C5 10⁻⁴ ~m
- D24 10⁻⁴ ~m
Correct answer
B. 2 10⁻⁴ ~m
Step-by-step solution
Given, distance between source and screen, D=2 ~m Distance of first minimum from the central maximum, y=5 ~mm =5 10⁻³ ~m Wavelength, =5 10⁻⁷ ~m We know that, y_ n = n D d For first minimum, n=1 aligned & & y₁ &= D d & & d &= D y₁ = 5 10⁻⁷ 2 5 10⁻³ =2 10⁻⁴ ~m aligned