Advertisements
Advertisements
प्रश्न
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
What would be the image distance if the object distance was 90 cm?
उत्तर
Lens formula is given by:
`1/f=1/v-1/u`
`1/20=1/v-1/-90`
⇒`1/20=1/v+1/90`
⇒`1/v=1/20-1/90`
⇒`1/v=(9-2)/180`
⇒`1/v=7/180`
⇒`v=180/7`
⇒`v=25.7`cm
The image distance will be 25.7 cm if the object distance is 90 cm.
APPEARS IN
संबंधित प्रश्न
An object is placed at a distance of 15 cm from a convex lens of focal length 20 cm. List four characteristics (nature, position, etc.) of the image formed by the lens.
A ray of light travelling in water emerges into air. Draw a ray-diagram indicating the change in its path.
If an object is at a considerable distance (or infinity) in front of a convex lens, where is the image formed?
Name one simple optical instrument in which the above arrangement of convex lens is used.
A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:
(a) 8 cm
(b) 16 cm
(c) 24 cm
(d) 32 cm
A convex lens of focal length 15 cm produces a magnification of +4. The object is placed:
(a) at a distance of 15 cm
(b) between 15 cm and 30 cm
(c) at less than 15 cm
(d) beyond 30 cm
Yesh find out F1 and F2 of symmetric convex lens experimentally then which conclusion is true.
State the position of object, position of image, nature of image when: Convex lens is used in observing biological specimens.
State the nature and position of the object on the principal axis to obtain a real image of the same size
