Answer
a). $f=10cm, R=20cm$
b). $3cm$
Work Step by Step
a). $\frac{1}{do}+\frac{1}{di}=\frac{1}{f}$
so, $\frac{1}{5}+\frac{1}{-10}=\frac{1}{f}$
or, $f=10 cm$
Radius of curvature = $2\times f=20cm$
b). Height of the image = $|\frac{10}{5}|\times1.5cm=3cm$
