The image formed by a concave lens for an object at infinity is:
virtual, erect, and point-sized
A concave lens is a diverging lens: parallel rays coming from an object at infinity spread out after passing through it, and only their backward extensions appear to meet. They appear to diverge from the focus on the same side as the object, so the image is always virtual and erect, never real.
When the object is at infinity, the rays converge (in their virtual extension) to the focal point F of the concave lens, so the image is formed at the focus and is reduced to a point. Hence it is virtual, erect, and point-sized.
"real, inverted, and large" and "real, erect, and magnified" are wrong because a concave lens can never form a real image of a real object. "virtual, inverted, and diminished" is wrong because a concave lens always gives an erect (not inverted) image.
Hence, the image is virtual, erect, and point-sized.
Which of the following is NOT the correct use of a concave mirror?
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:
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
The refractive index of crown glass is close to 3/2. If the speed of light in air is c, then the speed of light in the crown glass will be close to
Tyndall effect is a phenomenon of