Help! Electricity igcse physics qs make no sense

j3ssica jon3s

could someone tell me why the voltage change is different in these 2 qs?

(edited 11 months ago)

Screenshot 2023-05-08 at 6.09.37 PM.png145.8KB

Screenshot 2023-05-08 at 6.09.51 PM.png134.5KB

Reply 1

Eimmanuel

Study Forum Helper

Original post by j3ssica jon3s

could someone tell me why the voltage change is different in these 2 qs?

You did not show us the whole question. Where is the voltmeter located?
Is the voltmeter measuring the p.d. across the thermistor or other electrical component?

Reply 2

j3ssica jon3s

Original post by Eimmanuel

You did not show us the whole question. Where is the voltmeter located?
Is the voltmeter measuring the p.d. across the thermistor or other electrical component?

https://cdn.savemyexams.co.uk/uploads/2022/12/4ph1-1p-que-jan-2022.pdf its part of question 7

Reply 3

Eimmanuel

Study Forum Helper

Original post by j3ssica jon3s

https://cdn.savemyexams.co.uk/uploads/2022/12/4ph1-1p-que-jan-2022.pdf its part of question 7

In this circuit, the voltmeter is across the fixed resistor of a certain resistance value.
As the temperature decreases, the resistance of the thermistor increases, so the p.d. or voltage across the thermistor increases. But the p.d. or voltage across the 140 Ω-resistor will decrease, so the voltmeter’s reading decrease.
This is not very different from the circuit shown below. We are measuring the voltage across different electrical components.