Concepts Of Physics MCQ Edition [Volume 2]PhysicsThermal and Chemical Effects of Electric Current
A current is passed through a combination of two resistors connected in series, both possessing equal resistances. Disregard any change in resistance due to temperature variations. Over a specific time interval,
Options
- Aan equal rise in temperature must occur in both resistors
- Ban equal rise in temperature may occur in both resistors
- Cthe resistors must produce equal amounts of thermal energy
- Dthe resistors might produce unequal amounts of thermal energy
Correct answer
C. the resistors must produce equal amounts of thermal energy
Step-by-step solution
The thermal energy produced in a resistor is given by H = I^2Rt . Since both resistors are connected in series, the same current I flows through them. Given that their resistances R are equal, the thermal energy produced in both resistors over the same time interval t must be equal. The rise in temperature is given by T = H ms , where m is the mass and s is the specific heat capacity of the resistor. Since the material and mass of the two resistors are not specified, their heat capacities ( ms ) may or may not be e