Which of the following is NOT the correct use of a concave mirror?
It is used as a rear view mirror in automobiles.
A concave mirror is a converging mirror: it can produce a magnified, erect image of a nearby object and can focus parallel rays (like sunlight) to a point. These properties decide its uses.
A rear view mirror in automobiles is actually a convex mirror, not a concave one. A convex mirror always gives an erect, diminished image and a wider field of view, letting the driver see more of the traffic behind. So using a concave mirror as a rear view mirror is the incorrect statement.
The other options are genuine uses of a concave mirror: as a shaving mirror it gives an enlarged, upright image of the face when held close; in torches and headlights the bulb is placed at the focus so the reflected rays form a strong parallel beam; in a solar furnace it concentrates sunlight to a focal point to produce intense heat.
Hence, the use that is NOT correct is that of a rear view mirror in automobiles.
The image formed by a concave lens for an object at infinity is:
The magnification of a concave mirror is −1. Which of the following statements is correct about the position of the object?
The power of a lens is given as the reciprocal of its:
When a parallel beam of light passes through a convex lens, after refraction it:
An image is formed at a distance of 30 cm from a convex mirror when the object is placed 40 cm from the mirror. The magnification produced by the mirror will be _______.
An object is placed at a distance of 40 cm from a convex lens of focal length 10 cm, such that an image is formed at a distance of X cm from the lens. What is the value of X?
Two convex lenses have focal lengths of 50 cm and 25 cm, respectively. If these two lenses are placed in contact, then the net power of this combination will be equal to
Tyndall effect is a phenomenon of
A lens has a power of +2.0 Dioptre, Which one of the following statements about the lens is true?