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Question
State the condition of the following:
A lens has both its focal lengths equal.
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Solution
If the medium on both sides of the lens is same, the first and second focal lengths are equal.
RELATED QUESTIONS
What is a lens?
A ray of light after refraction through a lens emerges parallel to the principal axis of the lens. The incident ray either passes through ______.
Distinguish between a real and a virtual image.
The diagram given below shows the position of an object OA in relation to a converging lens whose foci are at F1 and F2.
Describe how the distance of the image from the lens and the size of the image change as the object is moved towards F1.
A ray of light incident at the optical centre of lens, passes undeviated after refraction.
State the condition of the following:
A ray passes undeviated through the lens.
Make the rrect choices in the following items :
ln fig, , a real image of a point objert O is formed, Which of the following statements is true about each of the arrangements?
(i) The object is at the principle focus of the lens
(ii) The focal length of the lens is 17 cm
(iii) lf the mirror is moved so that it is 6 cm from the lens image will also move
How will you differentiate between a convex and a concave lens by looking at a distant object.
The diagram showed a lens as a combination of one glass block and two prisms. Complete the ray diagram and show the part of the incident ray AB after passing through the lens.
(i) Name of the lens formed by the combination.
(ii) What is the line XX’ called?
(iii) Mark the focus F.
