A fixed resistor is connected across a steady direct-current source so that it…
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A fixed resistor is connected across a steady direct-current source so that it carries a constant current.
(i) State the definition of electrical power.
(ii) Starting from the work done in moving charge through a potential difference, derive the expression P=VI for the power supplied to the resistor.
(iii) Using Ohm’s law, show that P=I2R=RV2.
(iv) The resistor has resistance 25Ω and carries a current of 2.0A for 5.0min. Calculate the electrical energy converted into heat during this interval. Express your answer both in joule and in kilowatt-hour.