Anita Paul, Seema Sinha, Deepika Parashari and, Karuni Subrahmanyam Solutions for Exercise 2: Test paper

Explain shadow formations with diagrams for the case given below. 
When the source of light is bigger than the object.

Also, show the regions of umbra and penumbra.   

Underwater divers wear flippers. Why?

Convert:

$22.9 \mathrm{cm}$ into $\mathrm{mm}$.

Convert:
$608 \mathrm{cm} \mathrm{into} \mathrm{m}$

Convert:
$2.8 \mathrm{cm} \mathrm{into} \mathrm{km}$.

Convert:
$9002 \mathrm{km} \mathrm{into} \mathrm{m}$.

While measuring the length of a pencil, the reading of the scale at one end is $6.5 \mathrm{cm}$ and that at the other end is $17.8 \mathrm{cm}$. What is the length of the pencil?

You are given a sheet of transparent glass and a book. Which of them will cast a shadow when placed in front of a source of light? Justify.