# Your question: What do you mean by second principal focus of a concave lens?

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The second principal focal point is that point where any light ray travelling towards the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.

## What is second principal focus of concave lens?

The second focal point for a concave lens is a point. F2 on the principal axis of the lens such that the rays of light incident parallel to the principal axis, after refraction from the lens, appear to be diverging from this point.

## What is second principal focus?

Second principal focus of a lens is that point on the principal axis of the lens where the image is formed when the object is at infinity. It is denoted by F2.

## What is meant by principal focus of concave lens?

Principal focus is a point on the principal axis of a concave lens from which a parallel beam of light rays, travelling parallel to the principal axis appears to come after passing through the concave lens.

## What is first and second principal focus of a concave lens?

For a concave lens, the first focal point is a point. F1on the principal axis of the lens such that. the incident rays of light appearing to meet at it, after refraction from the lens become parallel to the principal axis of the lens. The second focal point for a concave lens is a point.

## What is the first and second principal focus?

Primary or Principal focus is defined as the point on the principal axis of the lens at which if an object is placed, the image would be formed at infinity. On the other hand, secondary focus of a lens can be defined as a point on which parallel rays after getting refracted from the lens converge at.

## What is principal focus of concave mirror Class 10?

Light rays that are parallel to the principal axis of a concave mirror converge at a specific point on its principal axis after reflecting from the mirror. This point is known as the principal focus of the concave mirror.

## What is the second principal focus of a convex lens?

(ii) Second Principal Focus (F2) : The second principal focus (F2) of a convex lens is the position of an image point on the principal axis of the lens, for which the object is situated at infinity. It is usually denoted by the letter ‘F2’ as shown in the figure (b).

## Why do lenses have two focus?

A lens has two focal points, because a lens has two refracting surfaces. A mirror has only one reflecting surface and hence, it has only one focal point.

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## What is principal focus and principal axis?

The principal axis of a lens is a line passing through the optical centre of the lens and perpendicular to both the faces of the lens. The principal focus of a convex lens is a point on its principal axis to which light rays parallel to the principal axis converge after passing through the lens.

## Where is principal focus of concave lens?

Therefore, the principal focus of a concave lens is a point on the principal axis of a convex lens, from where a parallel beam of light rays, travelling parallel to the principal axis, after passing through the lens, appears to come.

## What is principal focus of concave and convex lens?

The principal focus of a lens is defined as the point through which a parallel light after refraction passes through in the case of a convex lens and appears to pass through in the case of a concave lens.

## What is principal focus lens?

The principal focus of the convex lens is a point on the principal axis where the light rays appear to be meeting after refraction from the lens as shown in the figure.F in the figure is the principal focus.

## What is principal focus in physics class 10?

The principal focus is the point where a beam parallel to the principal axis converges or appears to diverge from a point on the principal axis after passing through the lens.

## How many principal focus does a lens have?

It is usually represented by the letter ‘F’. However a convex lens has two spherical surfaces and hence it has two principal foci or two focal points which are usually denoted by the letters ‘F1’ and ‘F2’ and are known as the first principal focus (F1) and the second principal focus (F2).

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