# A level Physics Question HELP

Thread starter 8 months ago
#1
C) A thermistor has a resistance of 800Ω at a temperature of 16∘C. It is wired in series with a fixed resistor and a 9.0V battery. A high-resistance voltmeter is connected to give a `temperature' reading.
[Note: that for this thermistor the resistance decreases as the temperature increases]

If the voltmeter needs to read 3.0V when the temperature is 16∘C, what is the resistance of the fixed resistor to 2 significant figures?

I cant get the answer for this question on isaac physics?
0
8 months ago
#2
What did you try? Send your working out please.

Is the voltmeter connected across the thermistor? You need to attach the diagram.

If it is you can work out the current through the circuit by 3 / 800. You can then work out the total resistance and subtract 800ohms from the total resistance.

You could also use the potential divider formula instead.
0
8 months ago
#3
(Original post by wiggo2013)
C) A thermistor has a resistance of 800Ω at a temperature of 16∘C. It is wired in series with a fixed resistor and a 9.0V battery. A high-resistance voltmeter is connected to give a `temperature' reading.
[Note: that for this thermistor the resistance decreases as the temperature increases]

If the voltmeter needs to read 3.0V when the temperature is 16∘C, what is the resistance of the fixed resistor to 2 significant figures?

I cant get the answer for this question on isaac physics?
What proportion of the total voltage is 3.0V?
What proportion of the total resistance does the thermistor need to be?
0
Thread starter 8 months ago
#4
(Original post by Driving_Mad)
What did you try? Send your working out please.

Is the voltmeter connected across the thermistor? You need to attach the diagram.

If it is you can work out the current through the circuit by 3 / 800. You can then work out the total resistance and subtract 800ohms from the total resistance.

You could also use the potential divider formula instead.
Sorry this is the wrong question! This one was 400ohms
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