Question 2
AIM: To verify the relationship between current and resistance at a constant voltage.
- Connect the circuit diagram as shown in figure 2.
- Ask the supervisor to check the circuit connection.
- Copy Table 2 in the answer booklet
Resistance(W) |
Current (A) |
Voltage(V) |
10 |
|
|
20 |
|
|
30 |
|
|
40 |
|
|
- Switch on the variac and set it to 10V
- Read and record the ammeter reading in Table 2.
- Switch off the variac.
- Repeat steps (d) to (f) for each corresponding total resistance value connected in series as shown in Table 2.
- Complete the Table 2.
- Plot a graph of current (A) on the vertical axis against resistance (W) on the horizontal axis
- Comment on the graph.
Observation
The expected answers were:
(a) Correct circuit connection
(b) Correct current entry
(c) correct voltage entry
(d) Correct axes
(e) Reasonable scale
(f) Plotting of points
(g) Line of best fit
(h) Comment on graph
Table 2
Resistance (Ω) |
Current (A) |
Voltage (V)= IR |
10 |
1 |
10 |
20 |
0.5 |
10 |
30 |
0.33 |
10 |
40 |
0.25 |
10 |
Comment on graph:
The graph satisfies the inverse proportionality, i.e. as voltage is kept constant and resistance is increased, current decreases.
The strengths and weaknesses candidates displayed in question 1are similar to the ones displayed here.