In Young's double slit experiment the ratio of intensitities of bright and dark fringes is 9 this means that

Options

A. the intensities at the screen due to the two slits are 5 units and 4 units, respectively
B. the intensities at the screen due to the two slits are 4 unit and 1 units, respectively
C. the amplitude ratio is 3
D. the amplitude ratio is 2

Answer

b.,d

Explanation

We know that
`(I_(max))/(I_(min)) = ((a + b)^(2))/((a - b)^(2))`
Where `I_(1) prop a^(2)` (a is amplitude of 1 wave) and `I_(2) prop b^(2)` (b is amplitude of 2 wave). Hence,
`(I_(max))/(I_(min)) = (9)/(1) implies (a + b)/(a - b) = (3)/(1) implies (a)/(b) = (1)/(2)`
`:. (I_(1)^(2))/(I_(2)^(2)) = (a^(2))/(b^(2)) = (1)/(4)`