Question

PHYSICS - ELECTRICITY.
1. Define the unit of electric potential..
2. What is resistance ? On what factors does the resistance of a conductor depend?
3. How does the resistance of a wire vary with its area of cross section ?
4. Relate one Joule and one Volt.
5. Define conductivity. What is its S.l unit ?
6. (a) Express Ohms law by a mathematical formula.
(b) Draw a circuit diagram to verify Ohms law.
(c) Present the relationship between the voltage applied across a conductor and the
cuttent flowing through it graphically.
7. What is the commercial unit of electrical energy? Relate KWh and Joule.
8. V-I graph for nichrome wire is a straight line passing through the origin and inclined
to the x-axis. What conclusion would you draw from the graph ?
9. How voltmeter and ammeter are connected in the circuit ? Why?
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Answer 1

1.....The electric potential is defined as the work done in moving 1 unit of positive charges from infinity to that point.

2.....Resistance is the ability of the conductor through which it opposes the flow of current.

The resistance of the conductor depends upon the following factors :-

(a) Length of the conductor

(b) Area of cross - section

(c) Nature of the material

(d) Temperature

3.....The resistance of a wire is indirectly proportional to the area of cross - section.

4.....1 volt is defined as when 1 joule of work is done in moving 1 coulomb of positive charges from one point to another.