Question

A fuse wire is always fitted in a porcelain casing. Why? What is an electromagnet? How can the strength of an electromagnet be increased?What is electric current? How its flows? Electromagnet is used in electric fan. Is it true? Explain. One of the important components of an electric bell are an armature. what is an armature? what is its role? what is mean by voltage difference?kindly explain this insimpleterms and words, also if possible give examples. what is resistance? what makes the metals to get varied resistance?kindly explain.

Answer 1

1) Porcelain is a bad conductor of electricity so it does not conducts electricity and moreover it is heat resistant so when the fuse heats and blows off it prevents any damage.

2) An electromegnet is a soft metal core (usually called ferrite) made into a magnet by the passage of electric current through a coil surrounding it. 

3) (a) By increasing the amount of current in the wires.
     (b) By increasing the number of turns around the soft iron core.

4)An electric current is a flow of electric charge. In circuits this charge is often carried by moving electrons in a wire. 

5)The current in a circuit is directed away from the positive terminal and toward the negative terminal of the battery. This is how it flows.

6)Armature is the piece of soft iron which gets attracted twards the electromagnet when the current flows through it . I further moves the striker so as to hit the bell .

7). The electric potential difference(Voltage difference) is the difference in electric potential (V) between the final and the initial location when work is done upon a charge to change its potential energy.

8)It is the degree to which a substance or device opposes the passage of an electric current, causing energy dissipation. R = V/I.

9) In metals the nature of substance can cause it to have varied resistance .

Answer 2

Answer:

see the picture dear.......