Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Wave Optics

Question:

Angular width of a central max. is $30^o$ when the slit is illuminated by light of wavelength 6000 Å. Then width of the slit will be approx.

Options:

12 × 10–6 m

12 × 10–7 m

12 × 10–8 m

12 × 10–9 m

Correct Answer:

12 × 10–7 m

Explanation:

$\text{Angular width } 2\theta = 30^o$

$sin 30^o = \frac{\lambda}{a}$

$a = \frac{\lambda}{sin30^o} = 2\lambda$

$ a = 12000A^o = 12\times 10^{-7}m$