Some students investigate electric circuits - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Question 3
Some students investigate electric circuits.
They set up this circuit.
What can the students do to increase the brightness of the lamp?
Put a cross (X) in the box n... show full transcript
Worked Solution & Example Answer:Some students investigate electric circuits - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Step 1
What can the students do to increase the brightness of the lamp?
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Answer
The students should put a cross next to option D: decrease the resistance of the variable resistor. Decreasing the resistance increases the current flowing through the circuit, which in turn increases the brightness of the lamp.
Step 2
(b)(i) Complete the circuit below with an ammeter and a voltmeter correctly connected.
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Answer
The ammeter should be connected in series with the lamp, while the voltmeter should be connected in parallel across the lamp. This configuration allows for the correct measurement of current and potential difference.
Step 3
(b)(ii) Calculate the potential difference (voltage) across the lamp.
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Answer
To find the potential difference (V) across the lamp, we can use Ohm's Law, which states:
V=IimesR
where:
I is the current (0.5 A)
R is the resistance (8 Ω)
Thus,
V=0.5imes8=4extV
Step 4
(c) Explain why only some of the electrical energy is transferred to light energy in the lamp.
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Only some of the electrical energy is transferred to light energy because not all energy used in the lamp is converted into light. Some energy is lost as heat due to resistance in the filament, which results in thermal energy rather than light energy.
Step 5
(d) Calculate the power being supplied to the lamp.
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Answer
The power (P) supplied to the lamp can be calculated using the formula:
P=VimesI
where:
