A given wood has a dimension of 2m length ,50cm width and 10cm thickness if it floats while 25% of its volume is above the water then what would be its mass

The duration of a photographic flash is related to an rc time constantly

Sorry i don’t know what to do

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.