A metallic resistor is connected one at a time to a variable d.c
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
A metallic resistor is connected one at a time to a variable d.c. supply whose internal resistance may be neglected. Throughout the experiment the temperature of the resistor is kept constant so that its resistance does not change.
(i) State the three standard expressions for electrical power in an electric circuit in terms of V, I and R.
(ii) If the potential difference applied to the resistor is doubled while its resistance remains unchanged, explain qualitatively how the power dissipated in the resistor changes.
(iii) Three resistors having resistances R, 2R and 21R are connected individually across the same ideal battery of emf V. Rank them in descending order of the power they dissipate and justify your ranking without performing detailed numerical calculations.