# Understanding Voltmeters: How They Measure Voltage in a Series Circuit

• asdasdasd
In summary, a voltmeter connected in series with a battery and resistor will register the terminal voltage of the battery, which means that the voltmeter will measure the voltage drop across the internal resistance of the battery. Depending on the circuit setup, the voltmeter may also measure zero or the voltage drop across the resistor. However, if the circuit only consists of the battery, resistor, and voltmeter, the answer would be the terminal voltage of the battery.
asdasdasd
A voltmeter connected in series with a battery and resistor will register:

a: zero
b: the terminal voltage of the battery
c: the voltage drop across the internal resistance of the battery
d: the voltage drop across the resistor

Is it C?

I think B.

I think the question is ambiguous... what do you mean "in series"?

1) If "in series" means that the whole circuit is just the battery, the resistor and the voltmeter (one after the other and closed in a loop) and that you have the voltmeter "closing the circuit", then the answer is B, because the voltmeter blocks any current along it (at least if you consider it a "perfect" voltmeter) and therefore there is no voltage drop around the resistor.

2) If "in series means that there is a whole circuit around, and you "open" the circuit at some point after the voltmeter and the resistor and insert the voltmeter, the answer is A because the voltmeter would be measuring the voltage drop around itself.

Domenicaccio said:
2) If "in series means that there is a whole circuit around, and you "open" the circuit at some point after the voltmeter and the resistor and insert the voltmeter, the answer is A because the voltmeter would be measuring the voltage drop around itself.

It seems to me that all of the voltage is dropped in either case so you are measuring terminal voltage. Unless I misunderstand...

montoyas7940 said:
It seems to me that all of the voltage is dropped in either case so you are measuring terminal voltage. Unless I misunderstand...

Actually we probably don't know, there may be other batteries along the circuit. However I don't think that the question was about case 2), it makes much more sense if it meant that the only components in the circuit are the mentioned battery, the resistor and the voltmeter.

asdasdasd said:
A voltmeter connected in series with a battery and resistor will register:

a: zero
b: the terminal voltage of the battery
c: the voltage drop across the internal resistance of the battery
d: the voltage drop across the resistor

Is it C?

Draw the circuit, first without the resistor. Remove a section of the wire where the voltmeter would be placed. You should have an open circuit with a battery and two pieces of wire. Now what would the voltmeter read if it were placed in series (i.e. you put one probe on the first wire and the other probe on the second wire)?

Next draw the circuit with the resistor at the end of the first wire, place the voltmeter in the series again (i.e. one probe on the end of the resistor and the other probe on the remaining wire) and ask yourself the same question.

Hope that helps.

CS

## 1. What is electricity?

Electricity is a form of energy that results from the movement of electrons. It can be created in many ways, such as through chemical reactions, friction, or electromagnetic induction.

## 2. How does electricity flow?

Electricity flows through a circuit, which is a closed loop of conductive materials. The flow of electricity is caused by the difference in electrical potential, also known as voltage, between two points in the circuit.

## 3. What are conductors and insulators?

Conductors are materials that allow electricity to flow through them easily. Metals, such as copper and aluminum, are good conductors. Insulators, on the other hand, are materials that prevent or resist the flow of electricity. Examples of insulators include rubber, plastic, and glass.

## 4. What are the different types of electricity?

There are two main types of electricity: direct current (DC) and alternating current (AC). DC flows in one direction, while AC constantly changes direction. Most household and commercial electricity is AC, while batteries and some electronic devices use DC.

## 5. How is electricity measured?

Electricity is measured in units called watts (W) or kilowatts (kW). These units measure the rate at which energy is transferred. Other common units of measurement for electricity include volts (V) for voltage and amps (A) for current. This information is typically displayed on your electric bill or on your home's electrical panel.

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