Does focal length of a concave mirror negative?

The focal length of a concave mirror is negative because the focus of a concave mirror is in front of the mirror, on the left side. Whereas, The focal length of a convex mirror is positive because the focus of a convex mirror is behind the mirror, on the right side.

What is the focal length of a concave mirror is?

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.

Why is focal length of concave mirror is taken positive?

The distance between the pole P of the concave mirror and the focus F is the focal length of the concave mirror. Now, we know that the image formed by a concave mirror is always a real and inverted image and it is in front of the mirror. Thus, the focal length of the concave mirror is always taken as positive.

Is focal length negative?

The distance from the lens to the focal point is called the focal length. For converging lenses, the focal length is always positive, while diverging lenses always have negative focal lengths. However, these conventions are arbitrary, and physicists could just as easily have made the signs opposite.

How do you find the focal length of a concave mirror experiment?

Drag the screen by clicking on point A of the screen till you get a sharp image of the object. Measure the distance between the concave mirror and the screen with given metre scale. This measured distance is focal length of concave mirror. Repeat the process two or three times.

What is the focal length of a mirror?

The focal length ( f ) is the distance from a lens or mirror to the focal point ( F ). This is the distance from a lens or mirror at which parallel light rays will meet. (right) a concave mirror.

How focal length of convex mirror is positive?

(a) A convex mirror has a positive focal length because the focus of a convex mirror is on the right side and behind the mirror.

What is the focal length of concave and convex mirror?

The distance of principle focus F from the pole P of the spherical mirror is called focal length(f) of the mirror. In case of concave mirror F is a real point while in case of convex mirror F is a virtual point. Focal length of a concave and convex mirror is half the radius of curvature of the mirror.

Is focal length of concave lens 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.