2. What is the magnitude of the repulsive force between two pith balls (small, light balls
that are easily charged) that are 0.08 m apart and have equal charges of 3.0 x 10-8 C?'

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.

The density of the block of iron is lees than the density of mercury but the density of the block of iron is greater than the density of water

Perpendicular to the wave motion