(a)–(c) deal with different ways of expressing electrical power. (i) State any three…
PHYSICS · Subjective · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
(a)–(c) deal with different ways of expressing electrical power.
(i) State any three distinct algebraic expressions for electrical power in terms of the quantities current I, potential difference V and resistance R.
(ii) A resistor is connected across a constant 50V dc supply. The numerical value of the resistor is known but the current is not measured. Without doing any arithmetic, identify which one of the three expressions written in part (i) lets you obtain the power dissipated most directly. Give one reason for your choice.
(iii) If, instead, the current through the same resistor is measured while its resistance is unknown, which of the three expressions would you now select to evaluate the power? Justify your answer briefly.