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## How do you find the power of a concave lens of focal length 2 meters?

The given focal length of the concave lens is **f = -2 m**. It is negative because a concave lens always has a negative focal length. The unit of power is dioptre (D) and 1D = 1m^{–}^{1}.

## What is the power of concave lens of focal length 2 cm?

= **-50 dioptres**.

## What is the power of concave lens of focal length?

The power of the lens is the reciprocal of the focal length of the lens. We know that, The focal length is the negative for the concave lens. Hence, The power of the concave lens is **-0.5 D**.

## What is the focal length of a concave lens of power 2.0 D?

Focal length of the lens is **-50cm** or 0.5m.

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

= 100/50 = **2 dioptre**.

## What will be the power of a concave lens of focal length 0.5 m?

Answer: In the same way, a power of **-2.0D** means a concave lens of focal length -0.5m.

## How do you find the power of a lens if the focal length is CM?

To calculate the power of a lens needed to focus at a particular distance, first convert **that distance into centimeters, then divide 100 cm by that number**. The result is the dioptric power. For example, suppose an object is at 1/2 meter.

## 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.

## Can power of concave lens be positive?

The power of a lens is defined as the reciprocal of the focal length. … Converging (convex ) lenses have **positive focal lengths**, so they also have positive power values. Diverging (concave ) lenses have negative focal lengths, so they also have negative power values.

## What is the focal length of concave mirror?

Focal Length – **The distance between the pole P of the concave mirror and the focus F** is the focal length of the concave mirror. Thus, the focal length of a concave mirror can be estimated by obtaining a ‘Real image’ of a distant object at its focus, as shown in the figure.

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

We have to find the power of the concave lens. Therefore, the power of the lens is **-4diopters**. Diopter is the SI unit of power of the lens.