Question 2
AIM: To test candidates’ knowledge of lighting circuits.
- Connect the circuit as shown in Fig. 2.
- Ask the supervisor to check the circuit connection.
- With lamps L1, L2, L3, L4 and L5 in position and switches S1, S2, and S3 open, record in Table 2 the state of the lamps as either ON or OFF.
- Repeat step (c) for the other tests in Table 2.
- In test IX, comment on the intensity of Lamp L3.
- In test XIII, comment on the intensity of Lamp L5.
- State two precautions taken in carrying out the experiment.
Table 2
Test |
Condition of switches/lamps |
L1 |
L2 |
L3 |
L4 |
L5 |
I. |
S1 open, S2 open, S3 open |
|
|
|
|
|
II. |
S1 closed, S2 open, S3 open |
|
|
|
|
|
III. |
S1 closed, S2 closed, S3 open |
|
|
|
|
|
IV. |
S1 closed, S2 closed, S3 closed |
|
|
|
|
|
V. |
S1 open, S2 closed, S3 open |
|
|
|
|
|
VI. |
S1 open, S2 open, S3 closed |
|
|
|
|
|
VII. |
S1 open, S2 closed, S3 closed |
|
|
|
|
|
VIII. |
S1 closed, S2 open, S3 closed |
|
|
|
|
|
IX. |
S1 closed, S2 closed, S3 closed, L1 removed |
R |
|
|
|
|
X. |
S1 closed, S2 closed, S3 closed, L5 removed |
|
|
|
|
R |
XI. |
S1 closed, S2 open, S3 closed, L3 removed |
|
|
R |
|
|
XII. |
S1 closed, S2 closed, S3 open, L2 removed |
|
R |
|
|
|
XIII. |
S1 closed, S2 closed, S3 open, L4 removed |
|
|
|
R |
|
XIV. |
S1 closed, S2 open, S3 closed, L5 removed |
|
|
|
|
R |
XV. |
S1 closed, S2 closed, S3 open, L5 removed |
|
|
|
|
R |
[Hint: R indicates that lamp is removed]
Observation
Table 2
Test |
Condition of switches/lamps |
L1 |
L2 |
L3 |
L4 |
L5 |
I. |
S1 open, S2 open, S3 open |
OFF |
OFF |
OFF |
OFF |
OFF |
II. |
S1 closed, S2 open, S3 open |
OFF |
OFF |
OFF |
OFF |
OFF |
III. |
S1 closed, S2 closed, S3 open |
ON |
ON |
OFF |
OFF |
ON |
IV. |
S1 closed, S2 closed, S3 closed |
ON |
ON |
ON |
ON |
ON |
V. |
S1 open, S2 closed, S3 open |
OFF |
OFF |
OFF |
OFF |
OFF |
VI. |
S1 open, S2 open, S3 closed |
OFF |
OFF |
OFF |
OFF |
OFF |
VII. |
S1 open, S2 closed, S3 closed |
OFF |
OFF |
OFF |
OFF |
OFF |
VIII. |
S1 closed, S2 open, S3 closed |
OFF |
OFF |
ON |
ON |
ON |
IX. |
S1 closed, S2 closed, S3 closed, L1 removed |
R |
OFF |
ON |
ON |
ON |
X. |
S1 closed, S2 closed, S3 closed, L5 removed |
OFF |
OFF |
OFF |
OFF |
R |
XI. |
S1 closed, S2 open, S3 closed, L3 removed |
OFF |
OFF |
R |
OFF |
OFF |
XII. |
S1 closed, S2 closed, S3 open, L2 removed |
OFF |
R |
OFF |
OFF |
OFF |
XIII. |
S1 closed, S2 closed, S3 open, L4 removed |
ON |
ON |
OFF |
R |
ON |
XIV. |
S1 closed, S2 open, S3 closed, L5 removed |
OFF |
OFF |
OFF |
OFF |
R |
XV. |
S1 closed, S2 closed, S3 open, L5 removed |
OFF |
OFF |
OFF |
OFF |
R |
(e) It becomes brighter/ It has higher intensity
(f) It becomes brighter/ It has higher intensity
(g) Precautions in carrying out the experiment
- Ensure tight connection
- Ensure the correct polarity of battery
- Switch off the circuit after recording readings and observation to
prevent battery drain.
Question 2 required candidates to connect a circuit with the provided diagram, follow a series of switching instructions and observe the lamps that were either ON or OFF at any instance. Majority of the candidates that attempted Question 2 responded very well.