Answer
a) $\lambda=480nm$
b) greater than 3.1 degrees
Work Step by Step
(a) We know that
$\lambda=\frac{sin\theta}{mN}$
$\lambda=\frac{sin(3.1^{\circ})}{2(560cm)(\frac{100cm}{1m})}$
$\lambda=480nm$
(b) We know that $sin\theta=Nm\lambda$. This equation shows that $sin\theta$ is directly proportional to the number of lines per centimeter. As the number of lines per centimeter increases, the angle for the second order maximum also increases and the angle for the second order maximum is greater than $3.1$.
