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## What distance from a convex lens is focal length 20 cm?

the answer is **40 cm** infront of the lens.

## How far should an object be placed from a convex lens of focal length 20cm to obtain its image at a distance of 90cm from the object?

An object should be placed at distance **60 cm** from the convex lens.

## How far from a convex lens of focal length 20cm would you place an object to get an image and last three times?

u= -2 x 20/3 = **-40/3 cm**. Answer: Between the centre of the curvature and its focus, if the image is real.

## At what distance the object should be placed from the lens of focal length 20cm so that it’s real and 2 times larger image is formed?

Since, the image is real, therefore magnification will be negative. Hence, object should be placed at a distance of **30 cm** from the optical center of the convex lens.

## Where will a convex lens of focal length 20cm?

A convex lens of focal length 20 cm is **placed coaxially with a convex mirror of curvature 20 cm**. The two are kept at 15cm apart from each other. A point object lies 60 cm in front of the convex lens. Draw a ray diagram to show the formation of the image by the combination.

## At what distance should an object be placed from a convex lens of focal length 10 cm?

Calculate the distance at which an object should be placed in front of a convex lens of focal length 10 cm to obtain a virtual image of double its size. Here, u=?,f=10cm,m=+2, as image is virtual. Therefore, object should be placed at a distance of **5 cm** from the lens.

## Where should an object be placed in front of a convex lens of focal length 20cm so as to obtain a two times magnified real image?

Answer Expert Verified

so if **you object be placed at the distance of 30 cm** then the two times magnified image will be obtain. hope it help you.

## Where must be an object placed in front of a convex lens of focal length 20 cm to obtain a real and four times magnified image?

If the lens has a focal length of 20 cm, the object must be positioned **40 cm in front of the lens**, creating an inverted image of the same size as the target, 40 cm behind the lens.

## What will be the focal length of concave mirror of radius of curvature of 1m?

The answer is **0.5 m**. Explanation: Focal length is the distance between the center of a lens and a convex or concave mirror.

## What is the distance from a concave lens of focal length to 10cm?

So the object should be placed at a distance of **6.7 cm** from the pole of the concave mirror (on the left, in front of the mirror).

## At what distance from the object should the lens be placed?

Answer: The object should be placed at **50 cm away** from the convex lens. Hence, The object should be placed at 50 cm away from the convex lens.

## What is the focal length of a lens with 0.5 D?

Note: The power of the lens is said to be 1 dioptre if the focal length of the lens is 1metre. That means, if the corrective power of the lens is +0.5D, the required lens is a convex lens of focal length **+2m**.