A parallel beam of light falls axially on a thin converging lens of focal length 20cm. The emergent light falls on a screen placed 30cm beyond the lens. An opaque plate with a triangular aperture, side 1 cm, is in contact with the lens
Which one of the following diagrams best shows to appearance of the patch of light seen on the screen?

An illuminated object is placed at a distance of 20 cm from a converging lens of focal length 15 cm. The image obtained on the screen is:

A converging beam of light is incident on a concave lens of focal length 20 cm. In the absence of the lens, the beam converges at a point 10 m behind the lens. Find where the beam will converge/diverge after refraction.

A converging beam of light is incident on a concave lens of focal length 20 cm. In the absence of the lens, the beam converges at a point 10 m behind the lens. Find where the beam will converge/diverge after refraction.

A parallel beam of light falls successively on a thin convex lens of focal length 40 cm and then ono a thin convex lens of focal length 10cm as shown in figure. In figure, the second lens is an equi-concave lens of focal length 10cm and made of a material of refractive index 1.5. In both the cases, the second lens has an aperture equal to 1cm. Q. Compare the area illuminated by the beam of light on the screen, which passes through the second lens in the two cases. The ratio (A_(2)//A_(1)) will be

A parallel beam of light is incident on a lens of focal length 10 cm. A parallel slab of refractive index 1.5 and thickness 3 cm is placed on the other side of the lens. Find the distance of the final image from the lens. .

A parallel beam of light is incident on a lens of focal length 10 cm. A parallel slab of refractive index 1.5 and thickness 3 cm is placed on the other side of the lens. Find the distance of the final image from the lens. .

A converging lens of focal length 5 cm is placed at a distance of 20 cm from a screen. How far from the lens should an object be placed so as to form its real image on the screen?

A beam of light converges at a point P. Now a convex lens of focal length 30 cm placed in the path of the convergent beam 12 cm from P. The point at which the beam converges now is