Chapter 24 - Physical Optics: The Wave of Nature of Light - Learning Path Questions and Exercises - Exercises - Page 840: 10

a). $(1)$ increase b). $1.92mm$ c). $2.4mm$

a). (1) increase as $\Delta y=\frac{Lv}{d}$, $v$ being the wavelength the distance between the maxima would decrease if the distance between the slits was increased. b). Now, $y_{n}=\frac{nLv}{d}$, n=1 $y=\frac{1\times 3\times 640\times 10^{-9}}{10^{-3}}=1.92mm$ c). $y_{n}=\frac{nLv}{d}$, n=1 $y=\frac{3\times 640\times 10^{-9}}{0.8\times10^{-3}}=2.4mm$