Force on Electron in Light Bulb Filament (240V, 6.0cm)

In summary, the question asks for the force on an electron in a filament of a light bulb, given a potential difference of 240V and a wire length of 6.0cm. To solve this, the equation F=qE is used, where E is calculated by dividing the potential difference by the wire length. This is because the potential difference is between the two end points of the wire that hold up the filament.
  • #1
BreadTomato
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Homework Statement



A filament in a light bulb uses a length of wire 6.0cm. The potential difference across the filament is 240V. What is the force on an electron in the filament from the imposed electric field?

Homework Equations



F= qE

E = V / d

The Attempt at a Solution



Hello everyone, thank you for reading this, from what I understand the solution is to substitute the E as V/d to solve this problem, however what I'm puzzled at is why does the length of the wire (6.0cm) is the 'd' in this equation? From what I understand, d is the separation between 2 plates of positive and negative charge, so I'm unsure as to why the 6.0cm applies.

Thank you very much!
 
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  • #2
Hello BT, :welcome:

A potential difference is between two positions. They can be simple points, or somewhat extended: a line or a plate.
In this exercise they are the end points of the thicker pieces of wire that hold up the filament.
 
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  • #3
BvU said:
Hello BT, :welcome:

A potential difference is between two positions. They can be simple points, or somewhat extended: a line or a plate.
In this exercise they are the end points of the thicker pieces of wire that hold up the filament.

Ahh I see, thank you very much kind sir!
 

Related to Force on Electron in Light Bulb Filament (240V, 6.0cm)

1. What is the force acting on an electron in a light bulb filament with a voltage of 240V and a length of 6.0cm?

The force acting on an electron in a light bulb filament can be calculated using the formula F = qE, where q is the charge of the electron and E is the electric field. In this case, the electric field can be calculated by dividing the voltage (240V) by the length (6.0cm), resulting in an electric field of 4000 V/m. When this value is multiplied by the charge of an electron (1.6 x 10^-19 C), the force on the electron in the light bulb filament is equal to 6.4 x 10^-16 N.

2. How does the force on an electron in a light bulb filament change with different voltages and filament lengths?

The force on an electron in a light bulb filament is directly proportional to the electric field, which is determined by the voltage and filament length. Therefore, the force will increase or decrease proportionally with changes in voltage and filament length. For example, doubling the voltage to 480V and keeping the filament length constant would result in a force of 12.8 x 10^-16 N on the electron, while doubling the length to 12.0cm and keeping the voltage constant would also result in a force of 12.8 x 10^-16 N.

3. What is the direction of the force on an electron in a light bulb filament?

The direction of the force on an electron in a light bulb filament is determined by the direction of the electric field. In this case, the electric field is pointing in the direction of the voltage, so the force on the electron will also be in that direction.

4. How is the force on an electron in a light bulb filament related to the brightness of the light bulb?

The force on an electron in a light bulb filament is not directly related to the brightness of the light bulb. The brightness of a light bulb is determined by the amount of current flowing through the filament, which is related to the number of electrons passing through the filament. The force on an electron only affects the movement of individual electrons, not the overall current.

5. Can the force on an electron in a light bulb filament be measured experimentally?

Yes, the force on an electron in a light bulb filament can be measured experimentally using a device called an electroscope. An electroscope can detect the presence and strength of an electric field, which can then be used to calculate the force on the electron. This type of experiment can also be done using a cathode ray tube, which uses an electron beam to demonstrate the effects of an electric field on electrons.

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