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QPage 351: Q7: HC Verma: Concepts of Physics - Volume 2 Electric Current through Gases Page 351: Q7 Solution: A diode valve is connected to a battery and a load resistance.…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often assume that electron emission leaves the cathode increasingly positive, forgetting that the external circuit (battery) continuously supplies electrons so the net charge of the cathode remains essentially neutral in steady state.

A diode valve is connected to a battery and a load resistance. The filament is heated, so that a constant current is obtained in the circuit. As the cathode continuously emits electrons, does it become more and more positively charged?

Step-by-Step Verified Solution

**Answer:** No, the cathode does not become more and more positively charged. **Step-by-Step Explanation:** In a diode circuit, the cathode is connected to the negative terminal of the battery. The battery continuously supplies electrons to the cathode, replenishing those emitted. Hence, the cathode remains neutral overall and does not accumulate positive charge .

All Questions in this Chapter

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