Electricity — Science STD 10 — Question

A boy is standing in front of and close to a special mirror. He finds the image of his head bigger than normal, the middle part of his body of the same size, and his legs smaller than normal. The special mirror is made up of three types of mirrors in the following order from top downwards:

A person finds difficulty in seeing nearby objects clearly. His vision can be corrected by using spectacles containing:

In a filament type light bulb, most of the electric power consumed appears as:

1. Visible light.
2. Infra-red-rays.
3. Ultraviolet rays.
4. Fluorescent light.

A student obtained a sharp inverted image of a distant tree on a screen placed in front of the concave mirror. He then removed the screen and tried to look into the mirror. He would now see

The strength of the magnetic field between the poles of an electromagnet would be unchanged if:

1. Current in the electromagnet winding were doubled.
2. Direction of current in electromagnet winding were reversed.
3. Distance between the poles of electromagnet were doubled.
4. Material of the core of electromagnet were changed.

If the key in the arrangement as shown below is taken out (the circuit is made open) and magnetic field lines are drawn over the horizontal plane ABCD, the lines are.

The magnetic field lines produced by a bar magnet:

1. Originate from the south pole and end at its north pole.
2. Originate from the north pole and end at its east pole.
3. Originate from the north pole and end at its south pole.
4. Originate from the south pole and end at its west pole.

Having two eyes gives a person:

1. Deeper field of view.
2. Coloured field of view.
3. Rear field of view.
4. Wider field of view.

A ray of light is incident on a plane mirror making an angle of 90° with the mirror surface. The angle of reflection for this ray of light will be:

How much energy does a 100W electric bulb transfer in 1 minute?

1. 100J.
2. 600J.
3. 3600J.
4. 6000J.