Electricity — Science STD 10 — Question

An illuminated object is placed at a distance of 20cm from a converging lens of focal length 15cm. The image obtained on the screen is:

1. Upright and magnified.
2. Inverted and magnified.
3. Inverted and diminished.
4. Upright and diminished.

To determine the focal length of a convex lens by obtaining a sharp image of a distant object we generally follow the following steps which are not in proper sequence.

1. Hold the lens between the object and the screen.
2. Measure the distance between the lens and the screen.
3. Select a well lit distant object.
4. Place a screen opposite to the object on the lab table.
5. Adjust the position of the lens to form a sharp image.

The correct sequence of these steps is:

A ray of light travelling in air goes into water. The angle of refraction will be:

The SI unit of energy is:

1. Joule.
2. Coulomb.
3. Watt.
4. Ohm-metre.

The lamps in a house hold circuit are connected in parallel because:

What does an electric generator generate?

Which of the following colour of white light is least deviated by the prism?

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

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:

Where should an object be placed in front of a convex lens to get a real image of the size of the object?

There are four fuels which all contain only carbon and hydrogen. The fuel having highest calorific value will be one which has:

1. More of carbon but less of hydrogen.
2. Less of carbon but more of hydrogen.
3. Equal proportions of carbon and hydrogen.
4. Less of carbon as well as less of hydrogen.