In a Young's double slit experiment,


In a Young's double slit experiment, 16 fringes are observed in a certain segment of the screen when light of wavelength $700 \mathrm{~nm}$ is used. If the wavelength of light is changed to 400 $\mathrm{nm}$, the number of fringes observed in the same segment of the screen would be :

  1. 24

  2. 30

  3. 18

  4. 28

Correct Option: , 4


(4) Let $n_{1}$ fringes are visible with light of wavelength $\lambda_{1}$ and $n_{2}$ with light of wavelength $\lambda_{2}$. Then

$\beta=\frac{n_{1} D \lambda_{1}}{d}=\frac{n_{2} D \lambda_{2}}{d}$   $\left(\because \beta=\frac{n \lambda D}{d}\right)$

$\Rightarrow \frac{n_{2}}{n_{1}}=\frac{\lambda_{1}}{\lambda_{2}} \Rightarrow n_{2}=\frac{700}{400} \times 16=28$


Leave a comment


Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now