- Un piano en una sala de conciertos emite una nota de frecuencia 494 [Hz]. una persona en las cercanías escucha esta nota como si fuera un LA (440 [Hz]). respecto a lo anterior, es correcto
afirmar que la persona
a) se aleja del piano.
b) se acerca al piano.
c) está en reposo muy lejos del piano.
d) está en reposo muy cerca del piano.
e) se mueve en círculos alrededor del piano

Amplify and switch electrical power and electronic signals

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.