## (i) Draw a labelled circuit diagram to study a relationship between potential difference (V) across the two ends of a conductor and the current (I) flowing through it. State the formula to show how I in a conductor varies when V across it is increased step wise. Show this relationship also on a schematic graph.

**
Answer
**

The formula ie.,
**
Ohm’s law
**
, states that the
**
current
**
passing through a conductor is
**
directly proportional
**
to the
**
potential difference
**
across its ends, provided the physical conditions like temperature, density etc. remain unchanged.

Graph showing relationship between V and I:

## (ii) Calculate the resistance of a conductor if the current flowing through it is 0.25

**
Answer
**

Given,

- I = 0.25 A
- V = 1 V

According to Ohm’s law,

**
V = IR
**

Where,

- V is potential difference
- I is electric current
- R is resistance

Therefore,
**
R
**
= V / I

= 1 / 0.25

=
**
4 ohm
**