An image of a bright square is obtained on a screen with the aid of a convergent lens. The distance between the square and the lens is 40cm. The area of the image is nine times larger than that of the square. Select the correct statement(s):

The image of an illuminated square object is obtained on a screen with the help of a converging lens. The distance of the square from the lens is 30 cm. The area of the image is 9 times of the square. What is the focal length of the ions ?

The image of a square hole in a screen illuminated by light is obtained on another screen with the help of converging lens. The distance of the hole from the lens is 40 cm. If the area of the image is nine times that of the hole, the focal length of the lens is

The real iamge of a square hole in screen, illuminated be light is obtained on another screen with the help of a converging lens. This distance of the hole from the lens is 20 cm. the are of the image is nine times that of the hole. What is the focal length of the lens ?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What ls this distance between the lens and the screen called?

Try this Material: Convex lens, screen, metre scale, stand for the lens etc. Method: Keeping the screen fixed, obtain a clear image of a distant object like a tree or a building with the help of the lens on the screen. Measure the distance between the screen and the lens with the help of the metre scale. Now tum the other side of the lens towards the screen. Again obtain a clear image of the distant object on the screen by moving the lens forward or backward. Measure the distance between the screen and the lens again. What will happen if you use a concave lens in this experiment?

The distance between the object and its real image from the convex lens is 60 cm and the height of image is two times the height of object . The focal length of the lens is

The distance between the object and its real image from the convex lens is 60 cm and the height of image is two times the height of object . The focal length of the lens is

The distance between an electric lamp and a screen is d=1m . A convergent lens of focal length f=21 cm is placed between the lamp and the lens such that a sharp image of the lamp filament is formed on the screen.