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प्रश्न
Explain the following term related to spherical lenses:- principal focus
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उत्तर
Principal Focus:-
The convex lens converge the rays incident on it after refraction, to a point on the principal axis. This point is known as principal focus of the convex lens. The rays incident on concave lens appear to diverge from a point on the principal axis. This point is known as the principal focus of concave lens.
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संबंधित प्रश्न
One half of a convex lens of focal length 10 cm is covered 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 a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.
Name the two types of spherical mirrors. What type of mirror is represented by the:
front side of a shining steel spoon?
A concave lens produces an image 20 cm from the lens of an object placed 30 cm from the lens. The focal length of the lens is:
(a) 50 cm
(b) 40 cm
(c) 60 cm
(d) 30 cm
Name the kind of mirror used to obtain
(a) a real and enlarged image
(b) a virtual and enlarged image
(c) a real and diminished image, and
(d) a virtual and diminished image.
Why does a driver use a convex mirror instead of a plane mirror as a rear view mirror?
Illustrate your answer with the help of a ray diagram.
Does the mirror name by your form a real image for all locations? Give a reason for your answer.
Define the term Centre of curvature.
Define the term Principle focus.
The minimum length of the mirror required to see the full image of the person is half ‘ of his height.
