Current through voltmeter and ammeter

• ravsterphysics
In summary, the conversation discusses the relationship between temperature, resistance, and voltage in a circuit with a thermistor. The resistance of the thermistor increases as temperature decreases, and this can affect the voltage measured by a voltmeter. However, the correct answer to the question posed is A because of the ideal properties of the voltmeter and ammeter. The voltmeter would measure the voltage across the thermistor, while the ammeter would not have any current passing through it.
ravsterphysics

3. The Attempt at a Solution

As temp decreases, the resistance of the thermistor increases...doesn't this mean that the voltmeter will increase too since V=IR?

I know that the total resistance of the circuit has increased so less current, but I put down option D but the correct answer is A?

Suppose that the voltmeter and ammeter are ideal and the cell has emf V. If at some moment the thermistor has a resistance R, what voltage would the voltmeter measure across R?

Albert Thomas
There's never any current through an ideal voltmeter, and never any voltage drop through an ideal ammeter.

1. What is the purpose of a voltmeter and ammeter?

A voltmeter is used to measure the voltage or potential difference across a circuit, while an ammeter measures the current flowing through a circuit. They are both essential tools for understanding the behavior of electrical circuits.

2. How is current measured with an ammeter?

An ammeter is placed in series with the circuit, meaning it is connected in-line with the current flow. The ammeter measures the amount of current passing through it and displays this value in amps.

3. How is voltage measured with a voltmeter?

A voltmeter is placed in parallel with the circuit, meaning it is connected to the two points between which the voltage is to be measured. The voltmeter measures the potential difference between these two points and displays this value in volts.

4. Is there a correct way to connect a voltmeter or ammeter to a circuit?

Yes, it is important to connect a voltmeter in parallel and an ammeter in series with the circuit. Connecting them incorrectly can cause inaccurate readings and potentially damage the instruments or the circuit.

5. Can a voltmeter or ammeter be used to measure AC and DC currents?

Yes, there are voltmeters and ammeters designed specifically for either AC or DC currents, and some can measure both types. It is important to use the appropriate instrument for the type of current being measured.

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