A parallel beam of light of wavelength `6000Å` gets diffracted by a single slit of width 0.3 mm. The angular position of the first minima of diffracted light is :

Options

A. `2xx10^(-3)` rad
B. `3xx10^(-3)` rad
C. `1.8xx10^(-3)` rad
D. `6xx10^(-3)` rad

Answer

A

Explanation

Here, `lambda=6000Å=6000xx10^(-10)m=6xx10^(-7)m`
`a=0.3mm=0.3xx10^(-3)m=3xx10^(-4)m`
For first minima, a `sintheta=lambda`, where a is the slit width
`sintheta=(lambda)/(a)=(6xx10^(-7)m)/(3xx10^(-4)m)=2xx10^(-3)`
As `sintheta` is very small so, `theta~~sintheta=2xx10^(-3)` rad