A student investigated how the current in a resistor varies with the potential difference across the resistor - AQA - GCSE Physics Combined Science - Question 1 - 2019 - Paper 1
Question 1
A student investigated how the current in a resistor varies with the potential difference across the resistor.
Figure 1 shows part of the circuit used.
The student... show full transcript
Worked Solution & Example Answer:A student investigated how the current in a resistor varies with the potential difference across the resistor - AQA - GCSE Physics Combined Science - Question 1 - 2019 - Paper 1
Step 1
The student connected an ammeter and a voltmeter into the circuit. What is the correct way to connect the ammeter and the voltmeter into the circuit?
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
The ammeter should be connected in series with the resistor, and the voltmeter should be connected in parallel with the resistor.
Step 2
The student increased the resistance of the variable resistor. How did increasing the resistance affect the current in the circuit?
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
Increasing the resistance caused the current to decrease.
Step 3
How should the student change the circuit to give negative values for current and potential difference?
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 obtain negative values for current and potential difference, the connections to the cell should be reversed.
Step 4
Name the type of relationship between current and potential difference for a resistor at constant temperature.
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
The relationship is directly proportional.
Step 5
Write the equation which links current, potential difference and resistance.
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
The equation is: potential difference = current × resistance, or V = IR.
Step 6
The current in the resistor was 0.12 A when the potential difference across the resistor was 3.0 V. Calculate the resistance of the resistor.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Using the formula V = IR, we can rearrange it to find R: R = V/I. Here, R = 3.0 / 0.12 = 25 Ω.
