Optics Question 899
(distance between slit and screen D = 12cm and distance between slits d = 5cm.) then the wavelength of the radiation used can be calculated using the formula λ = (dD)/L, where L is the distance between the central maximum and the first-order maximum.
Options:
A) 3/4 cm
B) 4 cm, 5cm
C) 2/3 cm, 2/5 cm
D) 4/3 cm, 5/3 cm
Show Answer
Answer:
Correct Answer: C
Solution:
[c] Path difference $ \sqrt{D^{2}+d^{2}}-D= \lambda $ .
Also, $ [\sqrt{D^{2}+d^{2}}-D]=(2n-1)\frac{\lambda }{2}\Rightarrow \lambda =\frac{2[\sqrt{D^{2}+d^{2}}-D]}{2n-1} $
For n= 1, 2, 3……………….. $ \lambda =2cm,\frac{2}{3}cm,\frac{2}{5}cm, $ …………….
BETA
