Distinguish between the terms ‘overloading’ and ‘short-circuiting’ as used in domestic circuits.

Overloading Short-circuiting Overloading occurs when an electric circuit draws more current than the permitted value. Short-circuiting occurs when the ends of a circuit are connected by a conductor of negligible resistance. To avoid overloading, too many appliances should not be connected and devices that draw a lot of currents should be avoided. To avoid short-circuiting, care should be taken while connecting the wires and the wires should not be left open.

Give two practical applications of an electromagnet.

As the name suggests electromagnet means temporary. It works like a magnet as long as the current passes through the coil. It is made of a soft iron core. Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Enable Ginger Cannot connect to Ginger Check your internet connection or reload the browser Disable in this text field Rephrase Rephrase current sentence Edit in Ginger ×

If a single coil of large number of turns is used in a motor, it is found that the motion of the coil is not smooth but jerky. Why is it so? How can this jerky motion be converted into a smooth circular motion?

In a motor, if a single coil is used, the force acts on the coil when the plane of the coil is parallel to the direction of the magnetic field of a permanent magnet. That means, the coil experiences a maximum force at 0 ° and 180 ° and no force at 90 ° and 270 ° . However, due to the momentum picked up by the coil during its rotation, it continues rotating till it covers 180 ° . This makes the motion of the coil jerky. To have smooth circular motion, a number of coils of many turns are wound on the same soft iron core at an angle of a few degrees to each other. Thus, when the magnetic couple tends to weaken in one coil, it becomes maximum in the other coil. This, on the whole, transforms the jerky motion into a smooth circular motion.

What is a solenoid? Can you determine the North and South poles of a current-carrying solenoid with the help of a bar magnet? Explain.

An insulated copper wire wound on some cylindrical shape, such that its length is greater than its diameter, and it behaves like a magnet when a current is made to flow through it, is called a solenoid. When electricity is passed through a wire which is in the shape of a coil of many circular turns wrapped closely, the magnetic field is produced as shown in the figure. From the figure, it is clear that the pattern of the field formed around the solenoid is similar to the magnetic field around a bar magnet. In fact, one end of the solenoid behaves as a magnetic north pole, while the other behaves as the south- pole. A bar magnet can be used to determine the poles of a current-carrying solenoid. When we bring the North pole of a bar magnet towards one end of a solenoid, If the magnet is repelled, that end is the North pole of the solenoid. If the magnet is attracted, that end is the South pole of the solenoid.