Question

A proton is moving at 105 m/s at a point where the potential is 10 V. Later, it is at a place where the potential is 5 V. What is its speed there, assuming energy is conserved?

105 m/s
Its speed will depend on how it got to the new place.
Less than 105 m/s
More than 105 m/s

Answer 1

More than 105 m/s

Step-by-step explanation:

Electric potential is defined as the work done in moving a charge from one point to another in an electric field.

Since the charge moved from a region of higher potential (10V) to a region of lower potential (5V) the speed is bound to increase because lesser work will be required to keep it moving; this implies that the kinetic energy will increase since the same amount of energy that kept it moving in the 10V region is still supplied to it ( energy is conserved).

Another simple way to help understand this is that whenever the potential energy of a particle decreases its kinetic energy increases; which implies that its velocity must have increased also, as long as the total energy of the system is conserved.