Advertisements
Advertisements
Question
Draw a diagram to show how a converging lens held close to the eye acts as a magnifying glass. Why is it usual to choose a lens of short focal length for this purpose rather than one of long focal length?
Solution
Magnifying glass:
A lens with a short focal length is used so as to obtain greater magnification.
APPEARS IN
RELATED QUESTIONS
An object is held 20 cm away from a converging lens of focal length 10 cm. Find the position of the image formed.
The image seen in a plane mirror cannot be formed on a screen. What name is given to this type of image?
Linear magnification produced by a concave mirror may be:
(a) less than 1 or equal to 1
(b) more than 1 or equal than 1
(c) less than 1, more than 1 or equal to 1
(d) less than 1 or more than 1
If a magnification of, −1 (minus one) is to be obtained by using a converging mirror, then the object has to be placed:
(a) between pole and focus
(b) at the centre of curvature
(c) beyond the centre of curvature
(d) at infinity
Explain what is meant by a virtual, magnified image.
At which position will you keep an object in front of a convex lens so as to get a real image of the same size as the object? Draw a figure.
At which position will you keep an object in front of convex lens to get a real image smaller than the object? Draw a figure.
An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm.
- Find the position of the image, and
- the magnification of the image.
The image of a candle flame formed by a lens is obtained on a screen placed on the other side of the lens. If the image is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens? What is the nature of the image at a distance of 80 cm and the lens?
What information about the nature of image is erect or inverted, do you get from the sign of magnification + or -?
