In YDSE, how many maxima can be obtained on the screen if wave length of radiation used is 200 nm and d = 700 nm

The condition for maxima $\mathrm{d} \mathrm{sin\theta } = \mathrm{n\lambda }$

for maximum path difference $\mathrm{d} = \mathrm{n\lambda }$

$\mathrm{n}=\frac{\mathrm{d}}{\mathrm{\lambda }}=\frac{700}{200}=3.5$

Hence 3rd order maximum is possible on both sides of central maximum.

Total 7 maximum can be observed.