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## What is the power of lens in 40 cm?

Power of first lens of 40 cm ,therefore power is **100/f= 1/40=2.5 Dioptre** …. since focal length is positive the lens is convex lens.

## What is the power of a concave lens of focal length 40cm?

The focal length of a concave lens is equal to -2.5 D

Hence in the above case it is given that the focal length is 40cm or 0.4m. So the power **=- 1/0.4= -2.5D** the sign is used to determine the type of lens used.

## What is power of lens of focal length of 20cm?

The power of a lens of focal length 20cm is **5D**.

So both lenses have same convergence of refracted light.

## What is power of lens of focal length of 20cm class 10?

so, 20 CM in metres= 20/100m=1/5 metres. power of a lens= **1/1/1/5=5 dioptres**……..

## What is the correct lens formula?

What is the Lens Formula? Answer: According to the convex lens equation, the lens formula is **1/f = 1/v + 1/u**. It relates the focal length of a lens with the distance of an object which is placed in front of it and the image formed of that object.

## What is the power of lens formula?

The power of a lens is defined as the reciprocal of its focal length in meters, or **D = 1/f**, where D is the power in diopters and f is the focal length in meters. Lens surface power can be found with the index of refraction and radius of curvature.

## What is the power of convex lens of focal length 80 cm?

∴ p = 1 80 × 10 2 = 100 80 = **1.25 D** .

## What is the power of a concave lens of focal length 50cm?

Answer: The power of a lens is 1/focal length (measured in meters). So, 50 cm is 1/2 meter, so the power is -2; D stands for diopters, the unit of power for lenses. Hence, the power of a concave lens of focal length 50 cm is **-2D**.

## What do concave lenses do?

A concave lens is a lens that possesses at least one surface that curves inwards. It is a diverging lens, meaning that it spreads out light rays that have been refracted through it. A concave lens is thinner at its centre than at its edges, and is **used to correct short-sightedness (myopia)**.

## What is the power of a lens of focal length 25 cm?

In this question it is given that the lens is convex, and its focal length is $25$ cm. First we will convert the focal length in meters. As it is a convex lens so its power is positive. Thus, the power of the lens is **$+ 4D$.**

## Can a concave lens make a real image?

**The concave lens will not produce real images**. Real images are not formed by a concave lens since the rays passing through the concave lens diverges and will never meet.

## What is the power of lens of focal length 10cm?

Answer: Convex lens have the ability to converge a parallel beam of light into a point. This point is called the focal point of the convex lens and the distance from the optical centre to the focal point is called the focal length. **p = 10 D.**