Electrical resistance is the opposition to current within a current .electrical resistance also explain the relationship between voltage and current.
An insulator is a material that provides resistance to the flow of electric current. Insulators include rubber, plastic, glass since they do not allow electricity to flow through them.
Output can not be greater than input because the conversion of energy can not be greater than 100%.
Answer:
The existance of dark energy was suggested to help explain measurements, using Type Ia supernovae as distance indicators, that the expansion of the universe is speeding up and its acceleration requires a source of energy. Scientists suggested that It may be a new form of energy for which there is not yet a theoretical explanation. quantum mechanics predict that it may be the vacuum energy associated with "empty" space itself.
