Electricity — Science STD 10 — Question

The product of petroleum used to drive heavy vehicles like trucks is:

1. Petrol.
2. Kerosene.
3. Diesel.
4. Carbon oxide.

If the focal length of a spherical mirror is 12.5cm, its radius of curvature will be:

Magnification produced by a convex mirror is always:

Which of the following is not attracted by a magnet:

1. Steel.
2. Cobalt.
3. Brass.
4. Nickel.

The minimum speed of wind necessary for the satisfactory working of a wind generator to produce electricity is about:

1. 15km/ h.
2. 25km/ h.
3. 35km/ h.
4. 45km/ h.

A ray of light in incident on one of the refracting face of the prism. It emerges out from its other side making an angle of emergence:

When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at he focus of:

Coulomb is the SI unit of:

Which of the following can make a parallel beam of light when light from a point source is incident on it?

1. Concave mirror as well as convex lens.
2. Convex mirror as well as concave lens.
3. Two plane mirrors placed at 90° to each other.
4. Concave mirror as well as concave lens.

The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?