Advertisements
Advertisements
प्रश्न
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
उत्तर
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
संबंधित प्रश्न
A ray of light is incident on a plane mirror at an angle of 30°. What is the angle of reflection
State the types of mirrors used for (i) headlights and (ii) rear view mirror, in cars and motorcycles. Give to justify your answer in each case.
Figure shows a concave mirror with its pole at P, focus F and centre of curvature C. Draw ray diagram to show the formation of image of an object OA.
State the position of object for which the image formed by a concave mirror is of same size.
(a) When a concave mirror is used as a shaving mirror, where is the person's face in relation to the focus of mirror?
(b) State three characteristics of the image seen in part (a).
Upto what maximum distance from a concave mirror, the image can be obtained? What will be the location of object for it?
Draw a ray diagram to show the formation of image of an object kept in front of a convex mirror. State three characteristics of the image.
For an incident ray directed towards centre of curvature of a spherical mirror the reflected ray:
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?
Find the height of the image of a body of height 1.5m in a mirror with a magnification of 1.5.
A concave mirror can be used to produce a parallel beam of light. Draw a ray to illustrate this.
Complete the following diagrams shown in the below figure by drawing the reflected ray for each incident ray.
If the real image of a candle flame formed by a lens 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?
