Combinations of Lenses & Mirrors
Trending Questions
Q. a stone is tied to the other end of light string of length l and made to rotate on vertical circle keeping other end at centre.if speed of stone at highest point is v>\sqrt{gl
Q. A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance d in cm will be
- 25
- 15
- 30
- 50
Q. In the situation shown in the figure, three lenses of focal lengths 20 cm, 30 cm and 36 cm are held coaxial such that separation between first and second lens is 12 cm and between second and third lens is 10 cm. If the final image of an object at a distance of 30 cm from first lens is at a distance 10x cm from the middle lens, then find the value of x.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/891953/original_6.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/891953/original_6.png)
Q. A concave mirror of focal length 10 cm and convex mirror of focal length 15 cm are placed facing each other 40 cm apart. A point object is placed between the mirrors on their common axis and 15 cm from the concave mirror. One of the images is produced by the reflection first at concave mirror and then at convex mirror. The distance of this image from convex mirror is
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/796002/original_3.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/796002/original_3.png)
- 6 cm
- 5 cm
- 4 cm
- 3 cm
Q. A vessel of depth 2h is half filled with a liquid of refractive index 2√2 and the upper half with another liquid of refractive index √2. The liquids are immiscible. The apparent depth of an object which has a height h2 from the bottom of the vessel inside the liquid as seen from the top of the vessel is
- 9h4√2
- 3h4√2
- 4h4√2
- 5h4√2
Q. A fish in a lake (refractive index of water is 43) is viewed through a convex lens. From water surface, the lens is placed in air at half of the distance of the fish from the water surface, so that the image is formed at the fish itself. The focal length of the lens is how many times the depth of fish in water?
Q. In the adjoining ray - diagram are given the positions of an object O, image I and two lenses L1 and L2. The focal length of L1 is also given. Find the focal length of the lens L2
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/934035/original_28.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/934035/original_28.png)
- 30 cm
- −30 cm
- −15 cm
- None of these
Q. In the adjoining ray-diagram are given the positions of an object O, image I and two lenses L1 and L2. The focal length of L1 is also given. Find the focal length of the lens L2.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/881576/original_101.png)
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/881576/original_101.png)
- 30 cm
- −30 cm
- −15 cm
- −60 cm
Q. A converging lens of focal length 15 cm and a converging mirror of focal length 10 cm are placed 50 cm apart with common principal axis. A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens. Find the locations of the two images formed.