How Does Changing the Voltmeter Affect Potential Difference Readings?

AI Thread Summary
Changing the voltmeter from a digital voltmeter with infinite resistance to a moving coil voltmeter with 500 ohms affects the potential difference readings in a circuit. The initial calculations show that the digital voltmeter records 3V and 5V for different configurations. When using the moving coil voltmeter, the user attempts to calculate the new readings using Ohm's law but arrives at an incorrect value of minus 7. The discussion emphasizes the importance of considering the voltmeter's resistance when measuring potential difference. Clarification on the steps taken to arrive at the new readings is requested for further assistance.
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potential difference?

Homework Statement


picture shown in attachment

The sliders are at the mid-point of the potential dividers.
1. Find the potential difference recorded by a digital voltmeter of infinite resistance connected as the voltmeter V in each circuit.
250/2 = 125
6/250=0.024A and 100/2=50
0.024*125 =3V 10/100=0.1A
0.1*50 = 5V



2. The digital voltmeter is replaced by a moving coil voltmeter of resistance 500 ohms. Calculate the new readings when using this meter.


?
For this question I have tried to work out the conductance, then from this the total resistance and Ohms law to find the current. Then using Ohms law again try to find the potential difference, but I came out with an answer of minus 7.


Homework Equations


V=IR (i think)


The Attempt at a Solution


"
?
For this question I have tried to work out the conductance, then from this the total resistance and Ohms law to find the current. Then using Ohms law again try to find the potential difference, but I came out with an answer of minus 7."
 

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#1 looks good.

For #2, can you show your steps in coming up with your answer?
 
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