What do you mean by the focal plane of a lens?

A lens has both its focal lengths equal.

A ray passes undeviated through the lens.

The diagram below shows a lens as a combination of a glass block and two prisms.

Name the lens formed by the combination.

The diagram below shows a lens as a combination of a glass block and two prisms.

What is the line $X{X}^{\text{'}}$ called?

The diagram below shows a lens as a combination of a glass block and two prisms.

Complete the ray diagram and show the path of the incident ray $AB$ after passing through the lens.

The diagram below shows a lens as a combination of a glass block and two prisms.

The final emergent ray will either meet $X{X}^{\text{'}}$ at a point or appear to come from a point on $X{X}^{\text{'}}$. Label the point as $F$. What is this point called?