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?
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To increase the brightness of the lamp, the students should decrease the resistance of the variable resistor. This allows more current to flow through the lamp, increasing its brightness.
Step 2
(b)(i) Complete the circuit below with an ammeter and a voltmeter correctly connected.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In the circuit diagram, connect the ammeter in series with the lamp and connect the voltmeter in parallel across the lamp. Ensure the symbols for both meters are accurate and clearly labeled.
Step 3
(b)(ii) Calculate the potential difference (voltage) across the lamp.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the potential difference (V) across the lamp, use Ohm's law, which states that V = I × R. Here, I = 0.5 A and R = 8 Ω.
Thus, the calculation is:
V=0.5extAimes8extΩ=4extV
The potential difference across the lamp is 4 V.
Step 4
(c) Explain why only some of the electrical energy is transferred to light energy in the lamp.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Only some electrical energy is converted to light energy in the lamp because not all energy is efficiently transformed. Some energy is lost as heat due to resistance in the filament, which is an inherent property of materials that always results in some energy being wasted during conversion.
Step 5
(d) Calculate the power being supplied to the lamp.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Power (P) can be calculated using the formula:
P=IimesV
Where I is the current and V is the potential difference. Given that I = 0.4 A and V = 5 V, we find the power:
