Before You Begin
Question #43360
The Question
Two identical perfectly black spherical resistors, each of surface area , are placed in a vacuum chamber whose walls are maintained at absolute zero (). The electrical resistance of each sphere varies with its absolute temperature according to the relation , where is the resistance at a reference temperature . Resistor 1 is connected to an ideal constant current source , while Resistor 2 is connected to an ideal constant voltage source . It is given that . Let the initial power dissipated at temperature be . If , where is the Stefan-Boltzmann constant and is a dimensionless positive constant, what is the ratio of the steady-state power dissipated by Resistor 1 to the steady-state power dissipated by Resistor 2, ?
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Multi-Concept_Bridge
Master problems that require linking physics and math concepts to solve complex competitive questions.
Concepts Behind This Question
Power Dissipation Ratio|Stefan-Boltzmann Power Law|Integration
Why This Question Is Tricky
Common Mistakes
This question tests the student's ability to couple electrical power dissipation with the Stefan-Boltzmann law under different circuit constraints (constant current vs. constant voltage).
The primary trap lies in assuming that since the initial power is identical for both resistors, their steady-state power dissipation will also be identical (leading to a ratio of 1).
Students often fail to recognize the feedback loop: temperature changes the resistance, which in turn alters the power dissipated differently depending on the source.
For a constant current source, power increases with temperature (), whereas for a constant voltage source, power decreases with temperature ().
Solving the resulting non-linear equilibrium equations ( vs ) is required to find the true steady-state power ratio.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Current Electricity - Class 12 |
| Concept | Power Dissipation Ratio |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |