The work done by the electric field in moving a charge is the negative of the potential energy difference between the two locations, which is the product between the magnitude of the charge q and the potential difference
:
The proton charge is
, and the two locations have potential of
and
, therefore the work is
Answer: particles move closer together
Explanation: If the motion of particles slows the particles move closer together. This is because the attraction between them pulls them toward each other. Strong attractive forces hold particles close together. As the motion of particles increases, particles move further apart.
To make sure the answer is correct
Question:
Consider a sample of helium gas in a container fitted with a piston as pictured below. The piston is frictionless, but has a mass of 10.0 kg. How many of the following processes will cause the piston to move away from the base and decrease the pressure of the gas? Assume ideal behavior.
I. Heating the helium. II.
II. toRemoving some of the helium from the container.
III. Turning the container on its side.
IV. Decreasing the pressure outside the container.
a) 0
b) 1
c) 2
d) 3
e) 4
Answer:
Only one process will cause the piston to move which is
i) Heating the helium
Explanation:
When helium is heated it becomes less dense or lighter. Heating the helium will cause an increase in volume which will make the piston to move away from the base. When the volume finishes increasing, the piston will stop moving which in turn will make the forces on both sides of the piston balanced, so the pressure inside will balance the weight of the piston and that of the atmosphere. From that we can see that there has been a pressure change as a result of heating.
