Question

In the Young's double slit experiment, intensities of black and bright fringes are $1$ and $4$ respectively, the ratio of amplitudes of sources will be :

• A. $1:1$
• B. $1:2$
• C. $3:1$
• D. $1:4$

Answer 1

Answer: (B)

$1:2$

$E=k{a}^2$
$\Rightarrow E\propto a^2$
or $\frac{a_1^2}{a_2^2}=\frac{E_1}{E_2}$
$=\frac{1}{4}$
or $\frac{a_1}{a_2}=\frac{1}{2}$.