Calculating Number of Electrons in a Copper Wire | Electric Field HW Help

In summary, a 90 cm long copper wire with a diameter of 1.00 mm and a mass of 6.35g has 29 protons in each copper atom and an atomic mass of 63.5. To find the number of electrons in the wire, we can use the equation mass of electron= 9.11x10^-31kg.F=k(q x q/r^2), but this does not work as atomic mass is related to kilograms. Instead, we can find the number of atoms in the wire by dividing the mass of the wire by the atomic mass, and then multiply by 29 to find the total number of electrons.
  • #1
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Homework Statement


A copper wire 90 cm long a 1.00 mm in diameter has a mass of 6.35g.

A) Find the number of electrons in the wire. (Copper has an atomic number of 29; that is there are 29 protons in the copper atom. Copper's atomic mass is 63.5)

B) There is one free electron per atom in copper. Find the number of free electrons in the wire.


Homework Equations



I'm not sure... but these might be helpful. mass of electron= 9.11x10^-31kg.F=k(q x q/r^2)

The Attempt at a Solution



I tried plugging into this equation but it does not work.
 
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  • #2
atomic mass is related to the kilograms. you have the mass of the wire, so using this find the no of atoms in the wire . no of atoms in the wire is mass of wire over atomic mass.
careful about the units
 

1. What is an electric field?

An electric field is a physical quantity that describes the strength and direction of the force experienced by an electrically charged object at any given point in space.

2. How is an electric field calculated?

An electric field is calculated by dividing the force experienced by an electrically charged object by the magnitude of the charge. It is also affected by the distance between the charged object and the point in space where the field is being measured.

3. What is the difference between an electric field and an electric potential?

An electric field is a vector quantity that describes the force experienced by a charged object, while electric potential is a scalar quantity that describes the energy associated with a charged object. In other words, electric potential is a measure of how much work is needed to move a charged object from one point to another, while electric field describes the force that would be exerted on the object at any given point.

4. How does the direction of an electric field relate to the direction of the force on a charged object?

The direction of an electric field is always in the direction that a positive test charge would move if placed in the field. The direction of the force on a charged object is in the opposite direction of the electric field, so if the electric field is pointing towards the positive charge, the force on a positive charge would be in the opposite direction.

5. What are some real-life applications of electric fields?

Electric fields have many practical applications, such as in electronic devices like smartphones and computers, in medical equipment such as MRI machines, and in power generation and distribution systems. They are also used in technologies like capacitive touch screens and electric motors.

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