Optics Question 198
Question: A slit of size 0.15 cm is placed at 2.1 m from a screen. On illuminated it by a light of wavelength 5 x 10^-5 cm. The width of central maxima will be
[RPMT 1999]
Options:
A) 70 mm
B) 0.14 mm
C) 1.4 mm
D) 0.14 cm
Show Answer
Answer:
Correct Answer: C
Solution:
Width of central maxima $ =\frac{2\lambda D}{d} $
$ =\frac{2\times 2.1\times 5\times {{10}^{-7}}}{0.15\times {{10}^{-2}}}=1.4\times {{10}^{-3}}m=1.4\ mm $
