Human Eye and Colourful World — Science STD 10 — Question

As light from a far off star comes down towards the earth:

The shape of the earth's magnetic field resembles that of an imaginary:

1. U-shaped magnet.
2. Straight conductor carrying current.
3. Current-carrying circular coil.
4. Bar magnet.

Which of the following terms does not represent electrical power in a circuit?

Choose the correct option.
The magnetic field inside a long straight solenoid-carrying current,

Which of the following ray diagrams is correct for the ray of light incident on a lens shown in Fig.?

If the index finger points towards the north and the middle finger towards the east, when using Flemings left-hand rule, what will be the direction of motion or that of the force acting on the conductor?

Which of the following statements is correct regarding the propagation of light of different colours of white light in air?

1. Red light moves fastest.
2. Blue light moves faster than green light.
3. All the colours of the white light move with the same speed.
4. Yellow light moves with the mean speed as that of the red and the violet light.

A non-renewable source of energy is:

1. Wood.
2. Alcohol.
3. Hydrogen gas.
4. Natural gas.

Why does a current carrying freely suspended solenoid rest along a particular direction?