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प्रश्न
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उत्तर
The parallel beam of light on reflection by a concave mirror converges at a point on the principal axis, midway between pole and the centre of curvature. This point is called the principal focus
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संबंधित प्रश्न
How is the position of an image related to the position of the object?
An insect is sitting in front of a plane mirror at a distance 1 m from it.
(b) What is the distance between the insect and its image?
An object is kept at 60 cm in front of a plane mirror. If the mirror is now moved 25 cm away from the object, how does the image shift from its previous position?
An optician while testing the eyes of a patient keeps a chart of letters 3 m behind the patient and asks him to see the letters on the image of chart formed in a plane mirror kept at distance 2 m in front of him. At what distance is the chart seen by the patient?
State two uses of a plane mirror.
In the barber's shop, two plane mirrors are placed :
A ray of light strikes a plane mirror, such that the angle with the mirror is 20°. What is the value of angle of reflection? What is the angle between the incident ray and the reflected ray?
Prove geometrically that when plane mirror turns through a certain angle, the reflected ray turns through twice the angle.
A boy stands 4 m away from the plane mirror. If the boy moves `1/2` m towards the mirror, what is now the distance between the boy and his image? Give a reason for your answer.
What must be the minimum length of a plane mirror in which a person can see himself full length? Draw a diagram to justify your answer. Does the distance of a person from the mirror affect the above answer?
