Question

show an activity to study the dependence of potential difference(v)across a resistor on the current (l) passing through it and determine its resistance. also plot a graph between v and l

Answer 1

"PROCEDURE

1. Set up the circuit arrangement as shown in circuit diagram or apparatus arrangement.

2. Note the least count of the ammeter and voltmeter.

3. Find, if any, zero error of the ammeter and voltmeter and record it in table ‘A’.

4. Plug the key/switch on the battery eliminator and adjust the rheostat by sliding its variable terminal till the ammeter and the voltmeter show a reading.

5. Note the readings of ammeter and voltmeter in table ‘B\ Take out the plug or switch off the battery eliminator for a moment.

6. Repeat the step 4 and 5 for the different values of current by varying the sliding terminal of rheostat.

7. Tabulate all the observations in the observation table ‘B’ and find the ratio of V /I for each set of observations. Find the mean value of R.

8. Plot a graph by taking / along y-axis and V along v-axis or V along .r-axis and I along y-axis.

"

Answer 2

"The experiment based on Ohm's Law that states that the "potential difference" (V) in an "electric circuit" is "directly proportional" to the "current" (I) "flowing through" the "circuit" under the "same temperature".

$V\quad \propto \quad I$

V = IR, where R is the constant.

$R\quad =\quad \frac { V }{ I }$, measured in Ohms.

The equipment required are ammeter, voltmeter, rheostat, resistor, and sandpaper. The ammeter is "connected in series" and voltmeter in parallel in the circuit. The "ammeter" and "voltmeter" are checked and readings are noted. The resistance is calculated by $R\quad =\quad \frac { V }{ I }$. A graph that represents the ammeter and voltmeter readings is plotted.

From the observations, it is proved that R remains the same at all times and is constant. The resistance R is the "ratio" of "V" and "I". The result of the graph proves Ohm's law because it shows $V\quad \propto \quad I$."