Magnetic Effects of Electric Current — Science STD 10 — Question

When we pay for our electricity bill, we are paying for the:

A piece of wire of resistance R is drawn to double its length. The new resistance is.

A 1.25kW heater works on a 220 B mains supply. What current rating would a suitable fuse have?

An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image

After testing the eyes of a child, the optician has prescribed the following lenses for his spectacles:
Left eye: +2.00D
Right eye: +2.25D
The child is suffering from the defect of vision called:

1. Short-sightedness.
2. Long-sightedness.
3. Cataract.
4. Presbyopia.

The phenomenon of electromagnetic induction is:

1. The process of charging a body.
2. The process of generating magnetic field due to a current passing through a coil.
3. Producing induced current in a coil due to relative motion between a magnet and the coil.
4. The process of rotating a coil of an electric motor.

Which scientist suggested that the magnet must also exert an equal and opposite force on the current?

A current-carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should passed in the conductor:

1. From top towards bottom.
2. From left towards right.
3. From bottom towards top.
4. From right towards left.

The magnetic field lines:

1. Intersect at right angles to one another.
2. Interest at an angle 45° to each another.
3. Do not cross one another.
4. Cross at an angle of 60° to one another.