Question

In a Young’s silt experiment, the angular width of a fringe formed on a distant screen is 1⁰.The slit separation is 0.01mm. The wavelength of the light is :

• A. 0.174 nm
• B. 0.174Å
• C. 0.174$\mu m$
• D. 0.174×10^-4m

Answer 1

Answer: (C)

0.174$\mu m$

Answer 2

Angular fringe width $\theta = \frac{\lambda}{d}$

$\therefore\lambda = \theta d$

Here, $d = 0.01$mm $= 10^{- 5}m$

$\theta = 1º = \frac{\pi}{180}radians$

$\lambda = \frac{\pi}{180} \times 10^{- 5} = 1.74 \times 10^{- 7}m$

$= 0.174 \times 10^{- 6}m = 0.174\mu m$