Activity 7.6:
Aim: To measure the current and voltage by using a suitable measuring apparatus.
Apparatus: Ammeter, voltmeter, connecting wire, switch, dry cell, crocodile clip, bulb and dry cell holder
(A) Measuring current using an ammeter
Instruction
1. Connect the circuit as shown in Photograph 7.8 using one dry cell.
2. Turn on the switch and record the reading of the ammeter. Observe the brightness of the bulb.
3. Record your observations.
4. Repeat steps 1 to 3 using two dry cells.
(B) Measuring the voltage using a voltmeter
Instruction
1. Connect the circuit as shown in Photograph 7.9 using one dry cell.
2. Turn on the switch and record the reading of the voltmeter. Observe the brightness of the bulb.
3. Record your observations.
4. Repeat steps 1 to 3 using two dry cells.
Observation
Questions
1. What is the relationship between the electrical current and the increase in the number of dry cells?
2. What is the relationship between the voltage and the increase in the number of dry cells?
3. Give an inference for the brightness of bulb in Activity A.
4. What is the relationship between the voltage, electric current and the brightness of the bulb?
Answer:
1. When the number of dry cells increase, the current increases.
2. When the number of dry cells increase, the voltage increases.
3. The brightness of the bulb increases because the current in the circuit increases.
4. When the voltage increases, the current increases and the brightness of the bulb increases.
Aim: To measure the current and voltage by using a suitable measuring apparatus.
Apparatus: Ammeter, voltmeter, connecting wire, switch, dry cell, crocodile clip, bulb and dry cell holder
(A) Measuring current using an ammeter
Instruction
1. Connect the circuit as shown in Photograph 7.8 using one dry cell.
2. Turn on the switch and record the reading of the ammeter. Observe the brightness of the bulb.
3. Record your observations.
4. Repeat steps 1 to 3 using two dry cells.
(B) Measuring the voltage using a voltmeter
Instruction
1. Connect the circuit as shown in Photograph 7.9 using one dry cell.
2. Turn on the switch and record the reading of the voltmeter. Observe the brightness of the bulb.
3. Record your observations.
4. Repeat steps 1 to 3 using two dry cells.
Observation
Questions
1. What is the relationship between the electrical current and the increase in the number of dry cells?
2. What is the relationship between the voltage and the increase in the number of dry cells?
3. Give an inference for the brightness of bulb in Activity A.
4. What is the relationship between the voltage, electric current and the brightness of the bulb?
Answer:
1. When the number of dry cells increase, the current increases.
2. When the number of dry cells increase, the voltage increases.
3. The brightness of the bulb increases because the current in the circuit increases.
4. When the voltage increases, the current increases and the brightness of the bulb increases.