Answer
(a) $2.00$
(b) $0.500$
(c) $2.00$
Work Step by Step
(a) We know that $W\theta=m\lambda$. This equation shows that if the wavelength is doubled then the diffracting angle will also be doubled. Thus, the pattern formed on the screen will have the width of the central bright spot doubled.
(b) We know that $\theta=\frac{m\lambda}{W}$. This equation shows that when the slit width is doubled then the diffracting angle is halved.
(c) We know that $Y=Ltan\theta$. This equation shows that if the distance between the slit and screen (L) is doubled then the linear distance or width of the spot on the screen is doubled.
