Home
Class 12
PHYSICS
In a convex lens of focal length F, the...

In a convex lens of focal length F, the minimum distance between an object and its real image must be

Text Solution

Verified by Experts

Since object and image is real
then object distance `= -x_(1)`
Image distance `=x_(2)`
`x_(0)=x_(1)+x_(2)`, `(1)/(x_(2))-(1)/(-x_(1))=(1)/(f)`
`rArr x_(1)+x_(2)=(x_(1)x_(2))/(f)`
`rArr d=(x_(1)(x_(1)-d))/(f)`
`rArrx_(0)=(x_(1)^(2))/(x_(2)-f)(dx_(0))/(dx_(1))=0`
`rArr x_(1)=2f`
which means `x_(2)=2f`
distance between object and image is `4f`
Promotional Banner

Similar Questions

Explore conceptually related problems

The minimum distance between an object and its real image formed by a convex lens is

The minimum distance between an object and its real image formed by a convex lens is

The minimum distance between the object and its real image for concave mirror is

A luminous object and a screen are at a fixed distance D apart. A converging lens of focal length f is placed between the object and screen. A real image of the object in formed on the screen for two lens positins if they are separated by a distance d equal to

An object is placed at a distance u from an equiconvex lens such that the distannce between the object and its real image is minimum. The focal length of the lens is f. The value of u is

A convex lens of focal length f is placed somewhere in between an object and a screen. The distance between the object and the screen is x . If the numerical value of the magnification produced by the lens is m , then the focal lnegth oof the lens is .

Choose the correct alternative corresponding to the object distance 'u', image distance 'v' and the focal length 'F' of a converging lens from the following . The average speed of the image as the object moves with the uniform speed from distance (3F)/(4) to (F)/(2) is greater than the average speed of the image as the object moves with same speed from distance (F)/(2) "to" (F)/(4) The minimum distance between a real object and its real image in case of a converging lens is 4F where F is its focal length.

The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convax lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image.

The real image which is exactly equal to the size of an object is to be obtained on a screen with the help of a convex glass of focal length 15 cm. For this, what must be in the distance between the object and the screen?

In an experiment for the determination of focal length of the convex mirror a convex lens of focal length 20cm is placed on the optical bench and an object pin is placed at a distance 30cm from the lens. When a convex mirror is introduced in between the lens and the real and inverted image of the object, the final image of object O is formed at O itself. If the distance between the lens and the mirror is 10cm, then the focal length of the mirror is