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A resistor is connected to a power supply - Edexcel - GCSE Physics - Question 8 - 2018 - Paper 1
Question 8
A resistor is connected to a power supply. The potential difference across the resistor is 6.0V. (i) Which of these corresponds to a potential difference of 6.0V? ... show full transcript
Worked Solution & Example Answer:A resistor is connected to a power supply - Edexcel - GCSE Physics - Question 8 - 2018 - Paper 1
Step 1
Step 2
Calculate, in minutes, the time taken for this amount of charge to flow through the resistor.
Answer
To calculate the time, use the formula:
Where:
- Q is the total charge (42 C)
- I is the current (200 mA = 0.2 A)
Rearranging gives:
t = \frac{Q}{I} = \frac{42}{0.2} = 210 \, seconds = \frac{210}{60} = 3.5 \, minutes$$Step 3
Step 4
Explain why the resistor becomes warm.
Answer
The resistor becomes warm due to the collisions between the electrons flowing through it and the lattice structure of the resistive material. As electrons collide with the lattice atoms, they transfer kinetic energy to the atoms, causing the lattice to vibrate more vigorously, which results in heat generation.
Step 5
Deduce how the resistors have been arranged inside the cardboard tube.
Answer
Given a total potential difference of 6.0 V across the resistors with a current of 1.2 A:
- The equivalent resistance (R) between P and Q can be calculated using Ohm's law, R = V/I:
- With each resistor being 100 ohms, they must be in parallel to achieve an equivalent resistance less than each individual resistor, hence:
- The resistors are connected in parallel.