Electricity — Science STD 10 — Question

The real image formed by a concave mirror is smaller than the object if the object is:

1. Between centre of curvature and focus.
2. At a distance greater than radius of curvature.
3. At a distance equal to radius of curvature.
4. At a distance equal to focal length.

The correct sequencing of angle of incidence, angle of emergence, angle of refraction and lateral displacement shown in the following diagram by digits 1, 2, 3 and 4 is:

Refractive index of diamond with respect to glass is 1.6. If the absolute refractive index of glass is 1.5, then the absolute refractive index of diamond is:

The refractive indices of four substance P, Q, R and S are 1.50, 1.36, 1.77 and 1.31 respectively. The speed of light is the maximum in the substance:

1. P
2. Q
3. R
4. S

The mirror used by a dentist to examine the teeth of a person is:

1. Convex.
2. Concave.
3. Plane.
4. Any one of the above.

An electric generator actually acts as:

An object is placed at the following distances from a concave mirror of focal length 15cm, turn by turn:

1. 35cm
2. 30cm
3. 20cm
4. 10cm

Which position of the object will produce:

1. A magnified real image?
2. A magnified virtual image?
3. A diminished real image?
4. An image of same size as the object?

The focal lengths of four convex lenses P, Q, R and S are 20cm, 15cm, 5cm and 10cm, respectively. The lens having greatest power is:

1. P
2. Q
3. R
4. S

Which of the following coloured light has the least speed in glass prism?

1. Violet.
2. Yellow.
3. Red.
4. Green.