Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Semiconductors and Semiconductor Devices
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Semiconductors and Semiconductor Devices
When a wire connects the two ends of a p - n junction,
When a wire connects the two ends of a - junction,
Options
- Aa steady current will exist from the -side to the -side
- Bno steady current will exist in the circuit
- Ca current might or might not exist depending on the resistance of the connecting wire
- Da steady current will exist from the -side to the -side
Correct answer
B. no steady current will exist in the circuit
Step-by-step solution
When the two ends of a - junction are connected by a wire, the circuit is closed but lacks any external source of electromotive force.
In thermal equilibrium, the drift current caused by the built-in electric field in the depletion region is exactly balanced by the diffusion current caused by the concentration gradient of charge carriers.
The built-in potential barrier cannot drive a steady current through the external wire. If a steady current were to flow, energy would be continuously dissipated as heat in the wire without any energy source, which violates the law of conservation of energy.
Therefore, the net current in the circuit remains zero and no steady current will exist.
In thermal equilibrium, the drift current caused by the built-in electric field in the depletion region is exactly balanced by the diffusion current caused by the concentration gradient of charge carriers.
The built-in potential barrier cannot drive a steady current through the external wire. If a steady current were to flow, energy would be continuously dissipated as heat in the wire without any energy source, which violates the law of conservation of energy.
Therefore, the net current in the circuit remains zero and no steady current will exist.