Answer
(a) less than
(b) $54^{\circ}$
Work Step by Step
We can solve parts (a) and (b) as follows:
$\Delta \lambda=\lambda^{\circ}-\lambda=\frac{h}{m_{\circ}c}(1-cos\theta)$
We plug in the known values to obtain:
$(0.6510-0.650)\times 10^{-9}m=(2.43\times 10^{-12}m)(1-cos\theta)$
This can be rearranged as:
$1-cos\theta=\frac{0.0010\times 10^{-9}m}{2.43\times 10^{-12}m}$
This simplifies to:
$\theta=54^{\circ}$
Thus, the scattering angle of the scattered photon is $53.9^{\circ}$, which is less than $152^{\circ}$.