Question 1
(a) Connect the circuit as shown in Fig 1.
(b) Copy Table 1 into your answer booklet.
Table 1
Task |
Reading |
Battery terminal voltage on load (switch closed) |
|
Battery terminal voltage off load (switch opened) |
|
Voltage across lamp 1 |
|
Voltage across lamp 2 |
|
Voltage across lamp 3 |
|
Voltage across lamp 4 |
|
(c) Measure and record in Table 1 the battery terminal voltage when switch S is opened.
(d) Close switch S.
(e) Measure and record in Table 1 the battery terminal when the switch S is closed.
(f) With switch still closed, measure the voltage drop across lamp1, lamp2 lamp3 and lamp 4 and record your readings in Table 1.
(g) Remove lamp 1 and record the state of other lamps.
Observation
The expected answers were;
(a) Correct copying of the Table in into the answer booklet
Table 1
Task |
Reading |
Battery terminal voltage on load (switch closed) |
2V – 14V |
Battery terminal voltage off load (switch opened) |
10V -12V |
Voltage across lamp 1 |
± 12V |
Voltage across lamp 2 |
± 12V |
Voltage across lamp 3 |
± 12V |
Voltage across lamp 4 |
± 12V |
(b) Battery terminal voltage reading when switch is opened (10V – 12V)
(c) Battery terminal voltage reading when switch is closed ( 2V – 14V)
(d) Voltage across each of lamps 1,2,3 and 4 ( ±12V each)
(e) The remaining lamp will still be on.
The candidates were required to determine a battery terminal voltage; no load and on load, voltage across four lamps connected in parallel.
The candidates' performance was reported to be below average in this question.