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3. (a) Which of these symbols is used to represent a thermistor in an electrical circuit? A B C D (b) A student investigates how the current in a lamp changes with the potential difference across the lamp - Edexcel - GCSE Physics - Question 3 - 2019 - Paper 1
Question 3
3. (a) Which of these symbols is used to represent a thermistor in an electrical circuit? A B C D (b) A student investigates how the current in a lamp changes w... show full transcript
Worked Solution & Example Answer:3. (a) Which of these symbols is used to represent a thermistor in an electrical circuit? A B C D (b) A student investigates how the current in a lamp changes with the potential difference across the lamp - Edexcel - GCSE Physics - Question 3 - 2019 - Paper 1
Step 1
Calculate the missing value of resistance using Ohm's Law
Answer
To find the missing resistance value when the potential difference is 2.2 V and the current is 0.18 A, we use Ohm's Law, which states that resistance (R) equals voltage (V) divided by current (I):
Using the provided values:
This rounds to 12 Ω when considering significant figures.
Step 2
Comment on the relationship between potential difference and resistance
Answer
The results indicate that resistance increases with potential difference. However, it is important to note that doubling the potential difference does not necessarily result in doubling the resistance. This implies a non-linear relationship, where resistive increases do not correspond proportionally with potential increments, indicating that the resistance is affected by other factors at varying levels of voltage.