Electric Potential Energy Video Lessons

Concept

# Problem: An alpha particle (α), which is the same as a helium-4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of -3.45×10-3 V.The charge and the mass of an alpha particle are qα = 3.20x10 -19 C and mα 6.68x10-27 kg, respectively.What is the value of the change in potential energy, ΔU=Uf−Ui, of the alpha particle? Express your answer in joules using three significant figures.

###### FREE Expert Solution

Work done

$\overline{)\begin{array}{rcl}\mathbf{W}& \mathbf{=}& \mathbf{q}\mathbf{·}\mathbf{∆}\mathbf{V}\end{array}}$

Kinetic energy,

$\overline{)\begin{array}{rcl}\mathbf{KE}& \mathbf{=}& \frac{\mathbf{1}}{\mathbf{2}}{\mathbf{mv}}^{\mathbf{2}}\end{array}}$

ΔV = -3.45x10-3 V

qa = 3.20x10 -19 C

ma 6.68x10-27 kg

Part a)

Change in kinetic energy is equal to work done.

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###### Problem Details

An alpha particle (α), which is the same as a helium-4 nucleus, is momentarily at rest in a region of space occupied by an electric field. The particle then begins to move. Find the speed of the alpha particle after it has moved through a potential difference of -3.45×10-3 V.

The charge and the mass of an alpha particle are qα = 3.20x10 -19 C and mα 6.68x10-27 kg, respectively.

What is the value of the change in potential energy, ΔU=UfUi, of the alpha particle? Express your answer in joules using three significant figures.