Is Focal length of concave lens positive or negative?

you can easily verify that the focal length is in the positive x direction for a convex lens while it is along the negative x direction for a concave lens. So f is positive for a convex lens and negative for a concave lens. The reason is the sign altering of v.Click to see full answer. Subsequently, one may also ask, is Focal length of concave mirror positive or negative?f, the focal length, is positive for a concave mirror, and negative for a convex mirror. When the image distance is positive, the image is on the same side of the mirror as the object, and it is real and inverted. When the image distance is negative, the image is behind the mirror, so the image is virtual and upright.Secondly, is focal length of a convex lens positive? The focal length is positive that is a convex lens. Then the focal point is real or the rays pass through the point. The negative sign denoted as the image is virtual or the rays do not pass through the image. Beside above, what is the focal length of a concave lens? Focal length is distance over which the parallel rays either converge or diverge. For convex lens the focal length is positive. On the other hand, the focal length of concave lens is negative. Thus, for convex lens, the focal length is a distance over which all the parallel rays will converge.Is Focal Length positive or negative?A positive focal length means that the focal point of the lens is on the other side of the lens from where the object is placed. On the other hand, a negative focal length means that the focal point is on the same side of the lens as where the object is placed.