Magnetic Effect of Current Physics - Magnetic Effect of Current

What energy conversion does take place in a generator when it is in use?

Why is the core of a transformer laminated?

Can a transformer work when it is connected to a D.C. source? Give a reason.

What is the function of a step-up transformer?

Name the principle on which functioning of a transformer depends.

A transformer lowers e.m.f. from 220 V to 15 V. If the number of turns in primary are 3520, how many turns are in the secondary coil?

A transformer lowers e.m.f. from 220 V to 15 V. If 400 W power is given in primary, calculate (i) the current in primary coil and (ii) the current in secondary coil.

A transformer lowers e.m.f. 220 V to 12 volts. If the number of turns in primary are 8800, how many turns are in secondary coil?

Applying e.m. f to primary coil is 210 V. If the number of turns in primary coil is 200 turns and that of in secondary coil is 20 turns, then find out the output voltage. Name the type of transformer.

State a law, which determines the direction of magnetic field around a current carrying wire.

The primary coil of a transformer has 200 turns while the secondary coil has 1000 turns. What type of transformer is this? if the input voltage is 10V, what will be the output voltage?

Describe a simple Experiment to demonstrate that there Exists a magnetic field around a current-carrying conductor.

State the two properties of the magnetic lines of force around a circular coil.

The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.

What is the function of a transformer in an a.c. circuit? How do the input and output powers in a transformer compare?

State Lenz's Law.

What is an electromagnet? List any two uses.

State Fleming's left hand rule.

A current-carrying solenoid is suspended so as to freely rotate in a horizontal plane. State in what direction will it rest. Give a reason for your answer.

or

When a solenoid that is carrying current is freely suspended, it comes to rest in a particular direction. Why does this happen?

A flat coil of wire rotates at a constant speed about an axis perpendicular to a uniform magnetic field. Draw a graph to show how the induced e.m.f. varies relative to the positions of the coil during its one complete rotation. At what position of the coil, the e.m.f. has the maximum value?