# Can focal length of convex lens be positive?

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## Can the focal length be negative in a convex lens?

If you are talking about a biconvex lens then it can not have a negative focal length if the surrounding medium is denser than the lens. But for a convex-concave lens, if R2>R1 and no>nlens, you can have a negative focal length.

## Is focal length of convex positive?

In convex lens, the focal length is positive.

## Is focal length of a convex lens positive or negative?

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.

## Can the convex lens be negative?

For a convex lens, focal length (f) is positive and for a concave lens, the value of f is negative. So by assigning signs to focal length in the power formula (PL=1f) we get negative value for concave lens and positive value for convex lens.

## Why is focal length of concave lens negative?

The power of the lens is the reciprocal of the focal length. A concave lens is a diverging lens, so it will always have a negative focal length. Therefore, the power of a concave lens is also negative.

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## Is focal length of concave mirror positive?

The focal length f of a concave mirror is positive, since it is a converging mirror. Figure 2.

## Why is focal length positive for convex lens?

Convex lens converges incident rays. Hence the rays to converge at a point in front of the lens. So image distance is positive here. We can easily clarify that the focal length is positive direction for a Convex lens while negative with concave lens.

## What is the formula of focal length of convex lens?

According to the convex lens equation, 1/f = 1/v + 1/u. It relates the focal length of a lens with the distance of an object placed in front of it and the image formed of that object. 2.

## Is the power of concave lens positive?

The power of the concave lens is negative. Concave lens surfaces have a virtual radius of curvature, and thus a negative curvature. Optical power is denoted by the same convention signs that are used for focal length.

## Which lens has positive power?

(a) Convex lens has positive power.

## Can a converging lens have more than one focus?

Lenses have two focuses, each on the two sides of the mirror. Converging lens can have more than one focus depending on where the object is and focuses have to have same distance from the centre.

## 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.

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## Is object distance ever negative?

Explanation: Object distance is always negative as per the sign conventions. … Such an image is produced when the object is kept at a distance less than the focal length of the lens.