Electricity — Science STD 10 — Question

The 'coolants' which can be used in the reactor of a nuclear power station are:

1. Liquid mercury and nitrogen dioxide.
2. Liquid sodium and carbon dioxide.
3. Liquid ammonia and carbon monoxide.
4. Liquid boron and uranium oxide.

Which of the following correctly describes the magnetic field near a long straight wire?

If you focus the image of a distant object, whose shape is given below, on a screen using a convex lens,

the shape of the image of this object on the screen would be:

A series of fast-moving still pictures can create an illusion of movement because:

An electric heater is rated 100W and 220V. If it is operated on 110V. The power consumption will be:

If the potential difference between the ends of a fixed resistor is halved, the electric power will become:

If an object is placed 21cm from a converging lens, the image formed is slightly smaller than the object. If the object is placed 19cm from the lens, the image formed is slightly larger than object. The approximate focal length of the lens is:

The blue colour of sky is due to:

1. Refraction of light.
2. Dispersion of light.
3. Diffraction of light.
4. Scattering of light.

The current passing through an electric kettle has been doubled. The heat produced will become:

The colour of white light which suffers the maximum bending (or maximum refraction) on passing through a glass prism is: