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## Are concave lens negative or positive?

The focal length of **a concave surface is negative**, whereas the focal length of a convex surface is positive. Therefore, for a lens, the power of a concave and convex lens is negative and positive respectively. Whereas, for a mirror, the power of concave and convex lens is positive and negative respectively.

## Is a positive lens concave or convex?

Difference Between Convex and Concave Lenses

Convex Lens |
Concave Lens |
---|---|

It is also called a positive lens due to positive focal length nature. | It is also called a negative lens due to negative focal length nature. |

e.g. Human Eye, Camera, etc. | e.g. Lights, Flashlights,etc. |

## Where is convex lens used?

Convex lenses are used in **microscopes, magnifying glasses and eyeglasses**. They are also used in the cameras to create real images of objects present at a distance.

## Is minus 1 eyesight bad?

The Numbers

Generally, the further away from zero you go (whether the number is positive or negative), the worse your eyesight and the greater the need for vision correction. So +1.00 and -1.00 are quite modest; **your eyesight isn’t too bad**, as you only need 1 diopter of correction.

## Are real images always inverted?

Real image is found when the rays of light converge at a point after reflection on a mirror or after refraction through a lens. … If we placed an object above the x-axis then by geometry the rays will converge below the axis. Therefore, the image formed will be an inverted image. Hence, **a real image is always inverted**.

## Is U positive for convex lens?

question_answer Answers(3) According to Cartesian sign convention, object distances (u) are always negative as the object is placed to the left of the mirror/lens. **Focal length (f) is positive for a convex lens** and convex mirror.

## What happens when you put a concave and convex lens together?

Hint: When a concave lens and a convex lens of the same focal length are in contact, then **the power of the lens combination will be zero and its focal length will be infinite**. Therefore, the combination behaves as a plane glass plate.

## What are examples of concave lenses?

**There are many examples of concave lenses in real-life applications.**

- Binoculars and telescopes.
- Eye Glasses to correct nearsightedness.
- Cameras.
- Flashlights.
- Lasers (CD, DVD players for example).

## Which lens has negative magnification?

Note the sign convention: a telescope with **two convex lenses (f1 > 0, f2 > 0)** produces a negative magnification, indicating an inverted image. A convex plus a concave lens (f1 > 0 >f2) produces a positive magnification and the image is upright.

## Which lens is used if the D value is negative?

The focal length of a convex lens is positive and that of a **concave lens** is negative.

## Which lens has negative focal length?

**A diverging lens** is said to have negative focal length. A diverging lens causes exiting rays to be more divergent coming out than thay were enetering the lens. A converging lens can form a real image or a virtual image of a real object.