Advertisements
Advertisements
Question
A student used a device (X) to obtain/focus the image of a well illuminated distant building on a screen (S) as shown below in the diagram. Select the correct statement about the device (X).
Options
This device is a concave lens of focal length 8 cm.
This device is a convex mirror of focal length 8 cm.
This device is a convex lens of focal length 4 cm.
This device is a convex lens of focal length 8 cm.
Advertisements
Solution
This device is a convex lens of focal length 8 cm.
Explanation:
The incident rays after passing through the lens converge at the focus. So, the device 'X' is a converging or a convex lens. The distance between the lens and the screen gives the focal length of the lens.
APPEARS IN
RELATED QUESTIONS
Explain the following term related to spherical lenses:- optical centre
Give one use each of a concave and a convex mirror.
When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper.
At which point of the spherical mirror the carbon paper is placed?
Define the terms focus and focal length of a concave mirror. Draw diagram to illustrate your answer.
Name the kind of mirror used to obtain :
A real and enlarged image
A point light source is kept in front of a convex mirror at a distance of 40 cm. The focal length of the mirror is 40 cm. Find the position of image.
An object 5 cm high forms a virtual image of 1.25 cm high, when placed in front of a convex mirror at a distance of 24 cm. Calculate:
- the position of the image
- the focal length of the convex mirror.
What is the relation between focal length and radius of curvature of a concave mirror?
Complete the following diagrams shown in the below figure by drawing the reflected ray for each incident ray.
