Advertisements
Advertisements
Question
A symmetric double convex lens is cut in two equal parts by a plane containing the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be
Options
2 D
3 D
4 D
5 D.
Advertisements
Solution
4 D
As the lens is cut along the principal axis, the two new lens will act as two double convex lenses. Even after cutting the lens, the radius of the curvature of the two new lens will remain the same as that of the original lens, with the power equal to the original lens.
APPEARS IN
RELATED QUESTIONS
Find the focal length of a lens of power −2.0 D. What type of lens is this?
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
You have two lenses A and B of focal lengths +10 cm and –10 cm, respectively. State the nature and power of each lens. Which of the two lenses will form a virtual and magnified image of an object placed 8 cm from the lens? Draw a ray diagram to justify your answer
Which type of lens has a positive power?
Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.
What is the nature of a lens having a power of + 0.5 D?
A converging lens has a focal length of 50 cm. The power of this lens is:
Define the term focal length of a lens.
How does the power of a lens change if its focal length is doubled?
Consider three converging lenses L1, L2 and L3 having identical geometrical construction. The index of refraction of L1 and L2 are \[\mu_1 \text{ and } \mu_2\] respectively. The upper half of the lens L3 has a refractive index \[\mu_1\] and the lower half has \[\mu_2\] following figure . A point object O is imaged at O1 by the lens L1 and at O2 by the lens L2placed in same position. If L3 is placed at the same place,
(a) there will be an image at O1
(b) there will be an image at O2.
(c) the only image will form somewhere between O1 and O2
(d) the only image will form away from O2.
A double convex lens has focal length 25 cm. The radius of curvature of one of the surfaces is double of the other. Find the radii, if the refractive index of the material of the lens is 1.5.
A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.
Consider the situation described in the previous problem. Where should a point source be placed on the principal axis so that the two images form at the same place?
Power of a lens is – 4D, then its focal length is
Define power of a lens. What is its unit? One student uses a lens of focal length 50 cm and another of –50 cm. What is the nature of the lens and its power used by each of them?
The focal length of a concave lens is 20 cm. The focal length of a convex lens is 25 cm. These two are placed in contact with each other. What is the power of the combination? Is it diverging, converging or undeviating in nature?
The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is ______ cm.
An object is kept at a distance of 1m from a lens of power +2D:
- Identify the type of lens.
- Calculate its focal length and distance of the image formed.
The lens of power + 1·0 D is ______.
