Help pls .. Which image shows an example of the strong nuclear force in action?

Positrons are spontaneously emitted from the nuclei of

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.

Which best describes the difference between internal and thermal energy?