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Fill in the following blanks with suitable words:
(a) Parallel rays of light are reflected by a ______ to a point called the principal focus.
(b) The focal length of a concave mirror is the distance from the principal focus to the ____.
(c) A______ converges rays of light whereas a ______ diverges rays of light.
(d) For a convex mirror, parallel rays of light appear to ___ from a point called the principal focus
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 burnt 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 than a white paper?
An object is placed at the following distances from a concave mirror of focal length 16 cm, turn by turn:
(a) 36 cm
(b) 32 cm
(c) 21 cm
(d) 9 cm
Which position of the object will produce:
(i) a magnified real image?
(ii) a magnified virtual image?
(iii) a diminished real image?
(iv) an image of same size as the object?
An object of size 9.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharp focused image can be obtained? Find the size and nature of image.
[Hint. Find the value of image distance (v) first. The screen should be placed from the mirror at a distance equal to image distance].
Which of the following are concave mirrors and which convex mirrors ? Shaving mirrors, Car headlight mirror, Searchlight mirror, Driving mirror, Dentist's inspection mirror, Torch mirror, Staircase mirror in a double- decker bus, Make-up mirror, Solar furnace mirror, Satellite TV dish, Shop security mirror.
The diagram shows a dish antenna which is used to receive television signals from a satellite. The antenna (signal detector) is fixed in front of the curved dish.
(a) What is the purpose of the dish?
(b) Should it be concave or convex ?
(c) Where should the antenna be positioned to receive the strongest possible signals ?
(d) Explain what change you would expect in the signals if a larger dish was used.
Two big mirrors A and B are fitted side by side on a wall. A man is standing at such a distance from the wall that he can see the erect image of his face in both the mirrors. When the man starts walking towards the mirrors, he finds that the size of his face in mirror A goes on decreasing but that in mirror B remains the same.
(a) mirror A is concave and mirror B is convex
(b) mirror A is plane and mirror B is concave
(c) mirror A is concave and mirror B is plane
(d) mirror A is convex and mirror B is plane