Screen is placed at a distance 60 cm from an object. A convex lens of focal length f is placed between object and screen and it is attempted that real image of object is formed on the screen. But real image could not be formed for any position of lens between object and screen.

Screen is placed at a distance 60 cm from an object. A convex lens of

1.	Screen is placed at a distance 60 cm from an object. A convex lens of focal length f is placed between object and screen and it is attempted that real image of object is formed on the screen. But real image could not be formed for any position of lens between object and screen.
Answer» f must be LESS than 15 CM. f must be GREATER than 15 cm. f must be less than 10 cm f must be less than 5 cm Solution :Real image of object is formed on the screen only when distance between object and screen is greater than 4f where f is the focal LENGTH of convex lens placed in between. Here 60 cm is the distance between object and screen and hence if focal length of lens is greater than 15 cm then for no position of lens we can obtain real image of object on screen. Hence, option (b) is correct.

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Screen is placed at a distance 60 cm from an object. A convex lens of focal length f is placed between object and screen and it is attempted that real image of object is formed on the screen. But real image could not be formed for any position of lens between object and screen.

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