
When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at the focus of:


Important Questions on Refraction of Light
A beam of parallel light rays is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the diagram below.
Which of the following could be inside the box?

A beam of light is incident through the holes on one side of a box and emerges out through the holes on its opposite side as shown in the following figure.
The box contains:


When an object is placed in front of lens , the image is real, inverted, magnified and formed at a great distance. When the same object is placed in front of lens , the image formed is real, inverted and same size as the object.
What is the focal length of lens ?

When an object is placed in front of lens , the image is real, inverted, magnified and formed at a great distance. When the same object is placed in front of lens , the image formed is real, inverted and same size as the object.
What is the focal length of lens ?

When an object is placed in front of lens , the image is real, inverted, magnified and formed at a great distance. When the same object is placed in front of lens , the image formed is real, inverted and same size as the object.
What is the nature of lens ?

When an object is placed in front of lens , the image is real, inverted, magnified and formed at a great distance. When the same object is placed in front of lens , the image formed is real, inverted and same size as the object.
What is the nature of lens ?

When a fork is seen through lenses and one by one, it appears as shown in the diagrams. What is the nature of (i) lens and (ii) lens ? Give reason for your answer.
