Write two differences between convex lens and concave lens.

Write two difference each between:
Real image and virtual image

Write two difference each between:
Refraction and reflection

Write two difference each between the converging beam and the diverging beam.

Complete the following ray diagrams: 

A candle of $2 \mathrm{cm}$ height is placed $15 \mathrm{cm}$ in front of convex lens of focal length $10 \mathrm{cm}$. Draw to find the position and size of the image.  

Complete the following ray diagrams:
Find the position of the lens and focal length of the lens and show its formation.

Complete the following ray diagrams:
What is $\mathrm{OO}\text{'}$ and complete the diagram by making a second ray?