Advertisements
Advertisements
Question
A small object is placed 150 mm away from a diverging lens of focal length 100 mm.
(i) Copy the figure below and draw rays to show how an image is formed by the lens.
Figure
(ii) Calculate the distance of the image from the lens by using the lens formula.
Advertisements
Solution
The image formed by the lens is virtual, erect and diminished in size.
(a)(ii) Object distance (u) = -150 mm = -15 cm (sign convention)
Focal length (f) = -100 mm = -10 cm (sign convention)
Image distance (v) = ?
Applying the lens formula, we have:
`1/v-1/u=1/f`
`1/v-1/-15=1/-10`
`1/v+1/15=-1/10`
`1/v=1/10-1/15`
`1/v=(-3-2)/30`
`1/v=(-5)/30`
`v=-6 cm `
APPEARS IN
RELATED QUESTIONS
One half of a convex lens of focal length 10 cm is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.
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).
We can obtain a real, enlarged and inverted image by a concave mirror.
Give one use each of a concave and a convex mirror.
A ray of light strikes a plane mirror at an angle of 40° to the mirror surface. What will be the angle of reflection?
What is the name of the phenomenon in which the right side of an object appears to be the left side of the image in a plane mirror?
What is the relation between the focal length and radius of curvature of a spherical mirror (concave mirror of convex mirror)? Calculate the focal length of a spherical mirror whose radius of curvature is 25 cm.
What is a spherical mirror?
Name the mirrors shown in Figure (a) and (b).
For what position of object, the image formed by a concave mirror is magnified and erect?
An object of length 4 cm is placed in front of a concave mirror at distance 30 cm. The focal length of mirror is 15 cm.
- Where will the image form?
- What will be the length of image?
Define the following term:
spherical mirror
Define the following term in relation to concave mirror.
Aperture
What is the relation between focal length and radius of curvature of a concave mirror?
Find the height of the image of a body of height 1.5m in a mirror with a magnification of 1.5.
The following figure shows a concave mirror with its pole (P), focus (F), and center of curvature (C). Draw a ray diagram to show the formation of the image of an object AB by the concave mirror.
Explain why a ray of light passing through the center of curvature of a concave mirror, gets reflected along with the same pattern.
What is “aperture”?
