Advertisements
Advertisements
Question
How will you differentiate between a convex and a concave lens by looking at a printed page?
Advertisements
Solution
On keeping the lens near a printed page, if the letters appear magnified, then the lens is convex, and if the letters appear diminished, then the lens is concave.
RELATED QUESTIONS
Explain optical centre of a lens with the help of proper diagram(s).
State the condition when a lens is called an equi-convex or equi-concave.
The diagram below shows a lens as a combination of a glass slab and two prisms.
- Name the lens formed by the combination.
- What is the line XX’ called?
- Complete the path of the incident ray AB after passing through the lens.
- The final emergent ray either meets XX’ at a point or appears to come from a point on XX’. Label it as F. What is this point called?
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 three characteristic of the image.
(a) Draw a sketch to show how a lens is able to produce an image of the sun on a paper screen.
(b)(i) Would you regard the rays from the sun as being divergent, parallel or convergent?
(ii) What is the name given to the point where such rays meet after they have passed through the lens?
(iii) How does the image of the sun sometimes burn a paper screen?
In the following diagram , the object and the image formed by the respective lenses are shown. Complete the ray diagram, and locate the focus. Find the focal length of the lens.
Make the rrect choices in the following items :
An object is placed 50 cm from a connverging lens of focal length 30 cm. The image produced would be
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
A lens forms the image of an object placed at a distance of 45 cm from it on a screen placed at a distance 90 cm on the other side of it. Name the kind of lens.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
