Find the position, nature and size of the image of an object 3 cm high place at a distance of 9 cm from a concave mirror of focal length 18 cm.

The radius of curvature of a concave mirror is 50 cm. Where should an object be placed in the mirror, so as to form its image at infinity? Justify your answer.

A perfecting reflecting mirror has an area of 1cm². Light energy is allowed to fall on it for an hour at the rate of 10 Wcm-2. The force that acts on the mirror is

Mr. Raghav, grade 6 teacher find that his students do not draw when he draws on the board. Every time he had to turn towards them to see whether they draw and label the diagrams. Arav, one of his student fixed two big convex mirrors at the two sides of the black board. With this Mr. Raghav was able to draw and also supervise his students through the mirror. All the students started doing their work property.

(i) Which characteristics of convex lens, let Mr. Raghav to do both his job at the same time?

(ii) What value did Arav and Mr. Raghav show?

The refractive index of lens flint glass is 1.65 and for alcohol, it is 1.36 with respect to air, then the refractive index of the dens flint glass with respect to alcohol is

An object is placed at the centre of curvature of a concave mirror. The distance between its image and the pole is

Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror and show the angle of incidence and angle of reflection on it.

Where should an object be placed in front of the concave mirror so as to obtain its virtual, erect and magnified image?