The circuit diagram below shows four resistors connected to a battery of emf E and internal resistance r - NSC Physical Sciences - Question 8 - 2022 - Paper 1
Question 8
The circuit diagram below shows four resistors connected to a battery of emf E and internal resistance r. The resistances of the ammeter and the connecting wires are... show full transcript
Worked Solution & Example Answer:The circuit diagram below shows four resistors connected to a battery of emf E and internal resistance r - NSC Physical Sciences - Question 8 - 2022 - Paper 1
Step 1
8.1 State Ohm's law in words.
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Answer
Ohm's law states that the current flowing through a conductor is directly proportional to the potential difference across it, provided the temperature and other physical conditions remain constant.
Step 2
8.2.1 Calculate the total external resistance of the circuit.
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Answer
To find the total external resistance, we first add the resistors in series and parallel combinations.
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Answer
Using the formula for voltage:
V=IimesR
Given that the current is 3.5 A and the total external resistance calculated is 6.75 Ω, the voltage across V1 can be found using the formula:
V1=3.5imesR1Ω=3.5imes1=3.5extV.
Step 4
8.2.3 How does the reading on voltmeter V2 compare to the reading on voltmeter V1?
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Answer
The reading on voltmeter V2 is GREATER THAN the reading on voltmeter V1 because it measures the total voltage supplied by the battery, whereas V1 measures only the voltage drop across the 1 Ω resistor.
Step 5
8.3.1 Define the term emf.
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Answer
The emf (electromotive force) of a battery is the maximum potential difference that the battery can provide to drive a current in a closed circuit.
Step 6
8.3.2 Is the learner's conclusion CORRECT? Choose from YES or NO.
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Answer
NO.
Step 7
8.3.3 Give a reason for the answer to QUESTION 8.3.2.
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Answer
The emf of the battery is always greater than the voltage readings due to the internal resistance within the battery.
Step 8
8.4.1 The power dissipated by the 4 Ω resistor.
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DECREASES.
Step 9
8.4.2 The reading on voltmeter V1.
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DECREASES.
Step 10
8.5 Explain the answer to QUESTION 8.4.2.
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Answer
When V2 replaces S, the overall current in the circuit decreases due to the increased resistance, leading to a lower voltage drop across the 1 Ω resistor, thus decreasing the reading on voltmeter V1.
