Q. No.If the critical angle for total internal reflection from a medium to vacuum is \(45^{\circ}\), the velocity of light in the medium is:
1.
\(1.5\times10^{8}~\text{m/s}\)
2.
\(\dfrac{3}{\sqrt{2}}\times10^{8}~\text{m/s}\)
3.
\(\sqrt{2}\times10^{8}~\text{m/s}\)
4.
\(3\times10^{8}~\text{m/s}\)
The power of a biconvex lens is \(10\) dioptre and the radius of curvature of each surface is \(10\) cm. The refractive index of the material of the lens is:
| 1. | \( \dfrac{4}{3} \) | 2. | \( \dfrac{9}{8} \) |
| 3. | \( \dfrac{5}{3} \) | 4. | \( \dfrac{3}{2}\) |
An object is placed on the principal axis of a concave mirror at a distance of \(1.5f\) (\(f\) is the focal length). The image will be at:
| 1. | \(-3f\) | 2. | \(1.5f\) |
| 3. | \(-1.5f\) | 4. | \(3f\) |
A plane-convex lens of unknown material and unknown focal length is given. With the help of a spherometer, we can measure the
| 1. | focal length of the lens. |
| 2. | radius of curvature of the curved surface. |
| 3. | aperture of the lens. |
| 4. | refractive index of the material. |
Suppose that the lower half of the concave mirror’s reflecting surface in the given figure is covered with an opaque (non-reflective) material. What effect will this have on the image of an object placed in front of the mirror?
| 1. | the image will show only half of the object |
| 2. | the image will show the whole of the object |
| 3. | the intensity of the image will be low |
| 4. | both (2) and (3) |
A mobile phone lies along the principal axis of a concave mirror, as shown in the figure. Then,
| 1. | the magnification is not uniform due to the length of the object along the principal axis. |
| 2. | the distortion of the image depends on the location of the phone with respect to the mirror. |
| 3. | both (1) and (2) |
| 4. | none of these |
An object is placed at \(10\) cm in front of a concave mirror with a radius of curvature of \(15\) cm. The magnification of the image is:
1. \(-3\)
2. \(3\)
3. \(1\)
4. \(-1\)
Suppose while sitting in a parked car, you notice a jogger approaching towards you in the side view mirror of \(R= 2~\text{m}.\) If the jogger is running at a speed of \(5~\text{m/s},\) how fast does the image of the jogger appear to move when the jogger is \(39~\text{m}\) away?
1. \( 5~\text{m/s}\)
2. \(\dfrac{1}{60}~\text{m/s}\)
3. \(\dfrac{1}{280}~\text{m/s}\)
4. \(10~\text{m/s}\)
The earth takes \(24~\text{h}\) to rotate once about its axis. How much time does the sun take to shift by \(1^{\circ}\) when viewed from the earth?
1. \(3~\text{minutes}\)
2. \(2~\text{minutes}\)
3. \(1~\text{minutes}\)
4. \(4~\text{minutes}\)
Light from a point source in the air falls on a convex spherical glass surface (n = 1.5 and radius of curvature = 20 cm) of a glass medium which extends till infinity on other side . The distance of the light source from the glass surface is 100 cm. At what position the image is formed?
| 1. | at a distance of 200 cm from the glass surface, in the direction of incident light. |
| 2. | at a distance of 100 cm from the glass surface, in the direction of incident light. |
| 3. | at a distance of 200 cm from the glass surface, in the opposite direction of incident light. |
| 4. | at a distance of 100 cm from the glass surface, in the opposite direction of incident light. |
© 2025 GoodEd Technologies Pvt. Ltd.