The slab of a refractive index material equal to \(2\) shown in the figure has a curved surface \(APB\) of a radius of curvature of \(10\) cm and a plane surface \(CD\). On the left of \(APB\) is air and on the right of \(CD\) is water with refractive indices as given in the figure. An object \(O\) is placed at a distance of \(15\) cm from pole \(P\) as shown. The distance of the final image of \(O\) from \(P\) as viewed from the left is:
1. | \(20\) cm | 2. | \(30\) cm |
3. | \(40\) cm | 4. | \(50\) cm |
The distance between a convex lens and a plane mirror is \(10\) cm. The parallel rays incident on the convex lens, after reflection from the mirror form image at the optical centre of the lens. Focal length of the lens will be:
1. | \(10\) cm | 2. | \(20\) cm |
3. | \(30\) cm | 4. | Cannot be determined |
An air bubble in a sphere having 4 cm diameter that appears 1 cm from the surface nearest to the eye when looked along diameter. If = 1.5, the distance of bubble from the refracting surface is
1. 1.2 cm
2. 3.2 cm
3. 2.8 cm
4. 1.6 cm
An observer can see through a pinhole the top end of a thin rod of height h, placed as shown in the figure. The beaker height is 3h and its radius h. When the beaker is filled with a liquid up to a height 2h, he can see the lower end of the rod. Then the refractive index of the liquid is
(1)
(2)
(3)
(4) 3/2
In an experiment of find the focal length of a concave mirror a graph is drawn between the magnitudes of u and v. The graph looks like
As the position of an object \((u)\) reflected from a concave mirror is varied, the position of the image \((v)\) also varies. By letting the \(u\) change from \(0\) to infinity, the graph between \(v\) versus \(u\) will be:
1. | ![]() |
2. | ![]() |
3. | ![]() |
4. | ![]() |
1. | 2. | ||
3. | 4. |
A glass prism is dipped in water as shown in figure. A light ray is incident normally on the surface AB. It reaches the surface BC after totally reflected, if
(a) (b)
(c) (d) It is not possible
A convex lens A of focal length \(20~\text{cm}\) and a concave lens \(B\) of focal length \(5~\text{cm}\) are kept along the same axis with the distance \(d\) between them. If a parallel beam of light falling on \(A\) leaves \(B\) as a parallel beam, then distance \(d\) in \(\text{cm}\) will be:
1. \(25\)
2. \(15\)
3. \(30\)
4. \(50\)
A medium shows relation between i and r as shown. If speed of light in the medium is nc then value of n is
(1) 1.5
(2) 2
(3) 2–1
(4) 3–1/2