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

When a spherical mirror is held towards the sun and its sharp image is formed on a piece of carbon paper for some time, a hole is burnt in the carbon paper. (a) What is the nature of spherical mirror ? (b) Why is a hole brnt in the carbon paper ? ( c) At which point of the spherical mirror the carbon paper is placed ? (d) What name is given to the distance between spherical mirror and carbon paper ? ( e) What is the advantage of using a carbon paper rather then a white paper ?

Answer the following questions: An erect image of an object is formed by a spherical mirror when the object is placed at a certain distance from the mirror. Just by looking at the image, can you identify the mirror as concave or convex? Explain.

Annu and Anand have concave and convex lenses respectively. They took lenses in sunlight and tried to burn two pieces of paper of equal areas and temperature . State which lens will burn the paper. Give the reason. Explain with the help of a diagram, why the other paper did not burn.

Answer the following questions : Anu and anand have concave and convex lenses respectively . They took lenses in sunlight and tried to burn two pieces of paper of equal areas and temperature . State which lens will burn the paper. Give the reason . Explain with the help of diagram, why the other paper did not burn.

A piece of paper appears black in sunlight. What will be its colour when seen in red light?

State the type of lens that can be used to burn paper in sunlight at noon.

A man is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm . The diameter of the sun is 1.39 xx 10^(9) m and the diameter of the sun's image on the paper is

A man is trying to start a fire by focusing sunlight on a piece of paper using an equiconvex lens of focal length 10 cm . The diameter of the sun is 1.39 xx 10^(9) m and the diameter of the sun's image on the paper is