# Electric field and voltage

• tuggler
In summary: Electric fields come in different strengths, and in this situation, the field between the plates is 9.5eV. The second question is about voltage between the plates, and its unit is V or mV.

## Homework Statement

Two parallel conducting plates are separated by 10.0 cm, and one of them is taken to be at zero volts.

a. What is the electric field strength between them, if the potential 6.65 cm from the zero volt plate (and 3.35 cm from the other) is 633 V?

b. What is the voltage between the plates?

V = Ed

## The Attempt at a Solution

For a I got 9.5 keV which was from the formula: (633V)/0.0665m = 9.5eV E3.

For b I don't know what to do? The electric field is uniform so the electric field is just 9.5E3 and the distance will be 10cm/2 = 5 cm. But how can I get the correct answer?

Last edited:
(a) 9.5keV seems awfully low - check your units?
I don't see how you got that figure from your stated calcuation: 633/0.035=18086.

(b) you know the electric field between the plates and you know the separation, and you have an equation which relates these two values to the voltage. What's the problem?

Why are you dividing the 10cm separation between the plates by 2 to the "the distance"? What distance is that?
If you have 6V in 6cm, how many volts do you have in 10cm?
If there are 633 in 6.65cm, how many in 10cm?

1 person
My mistake, its suppose to be 633/0.0665 = 9.5keV and it is the correct answer.

And I made a stupid mistake. I thought they said half way between the plates which is why I divided it by 2. Thank you very much! I know what to do now.

633V/0.0665m = 9.5keV
You appear to be out by a factor of about 10^23 - check units.
Apart from that - well done.

tuggler said:
My mistake, its suppose to be 633/0.0665 = 9.5keV and it is the correct answer.

And I made a stupid mistake. I thought they said half way between the plates which is why I divided it by 2. Thank you very much! I know what to do now.

The first question is about the electric field strength, and its unit is V/m or kV/m, or N/C.
eV is unit of work or energy, about 1.6 E-19 joule.

ehild

## 1. What is an electric field?

The electric field is a physical quantity that describes the force exerted on a charged particle by other charged particles. It is represented by electric field lines and is measured in units of volts per meter (V/m).

## 2. How is electric field related to voltage?

Electric field and voltage are closely related. Voltage is the measure of electric potential difference between two points, while electric field is the force per unit charge that causes this potential difference. In other words, voltage is the potential energy per unit charge, and electric field is the gradient of this potential energy.

## 3. How is electric field and voltage created?

Electric fields and voltages are created by the presence of charged particles. When charges are separated, a potential difference is created, which in turn creates an electric field. The strength of the electric field and voltage depends on the magnitude and distribution of the charges.

## 4. What is the difference between electric field and electric potential?

Electric field and electric potential are related but distinct concepts. Electric field is a vector quantity that describes the force on a charged particle, while electric potential is a scalar quantity that describes the potential energy per unit charge at a specific point in space. In other words, electric field tells us the direction and magnitude of the force, while electric potential tells us the amount of potential energy.

## 5. How is electric field and voltage measured?

Electric field and voltage can be measured using various instruments, such as a voltmeter or an electrometer. The electric field can also be measured indirectly by observing the motion of charged particles in the field. Voltage is typically measured in volts (V), while electric field is measured in volts per meter (V/m).