Which one of the following materials cannot be used to make a lens?

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be

Which of the following can make a parallel beam of light when light from a point source is incident on it?

Which of the following statements is true?

Magnification produced by a rear view mirror fitted in vehicles

The laws of reflection hold good for

A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.

Beams of light are incident through the holes A and B and emerge out of box through the holes C and D respectively as shown in the Figure. Which of the following could be inside the box?

The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in Figure. Which one of them is correct?

What is meant by power of a lens?

Which mirror is used as rear view mirror in vehicles and why?

A ray of light enters a rectangular glass slab of refractive index 1.5. It is found that the ray emerges from the opposite face of the slab without being displaced. If its speed in air is \(3\times { 10 }^{ 8 }\)m/s, then what is its speed in glass?

Find the power of a concave lens of focal length 2m.

What will happen to ray of light when it falls normally on a surface?

Define the principal focus of a concave mirror .

Name the type of mirror used in following situations. 
(a) Headlight of car 
(b) Side/ rear view mirror of a vehicle
(c) Solar furnace
Support your answer with reason. 

An object of size 7 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should the screen be placed, so that a sharp focussed image can be obtained? Find the size and nature of image.

State mirror formula. How does of change when object distance u from the mirror is changed?

A convex lens of focal length 20 cm can produce a magnified virtual as well as real image. Is this a correct statement? If yes, where shall the object is placed in each case for obtaining these images?

An object of height 5 cm is placed perpendicular to the principal axis of a concave lens of focal length 10 cm. Use lens formula to determine the position, size and nature of the image if the distance of the object from the lens is 20 cm.

The image of a candle flame placed at a distance of 30 cm from a spherical lens is formed on a screen placed at a distance of 60 cm from the lens. Identify the type of lens and calculate its focal length. If the height of the flame is 2.4 cm, find the height of its image

Name the type of mirrors used in the design of solar furnaces. Explain how high temperature is achieved by this device.

The image formed by a spherical mirror is real, inverted and is of magnification -2. If the image is at a distance of 30 cm from the mirror, where is the object place? Find the focal length of the mirror. List two characteristics of the image formed if the object is moved 10 cm towards the mirror.

A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of the candle screen and the lens as under
Position of candle = 12.0 cm
Position of convex lens = 50.0 cm
Position of the screen = 88.0 cm
(a) What is the focal length of the convex lens?
(b) Where will the image be formed if he shifts the candle towards the lens at a position of 31.0 cm?
(c) What will be the nature of the image formed if he further shifts the candle towards the lens?
(d) Draw a ray diagram to show the formation of the image in case c) as said above.

(i) One half of a convex lens of focal length 10 cm is convered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw ray diagram to justify your answer.
(ii) A 4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find nature, position and size of the image.

A student wants to project the image of a candle flame on the walls of school laborated by using a mirror
(a) Which type of mirror should he use and why?
(b) At what distance in terms of focal length 'f' of the mirror should he place the candle flame so as to get the magnified image on the wall?
(c) Draw ray diagram to show the formation of image in this case.
(d) Can he use this mirror to project a diminished image of the candle flame on the same wall? State 'how' if your answer is 'yes' and 'why not' if your answer is 'no'