Question

The rate of fall of the voltage across the capacitor in a filter used in a diode rectifier depends

• A. upon the difference of the capacitive reactance and load resistance
• B. inversely only on the capacitance
• C. directly on the product of the capacitance and load resistance
• D. upon the sum of the capacitive reactance and load resistance
• E. on the inverse of the product of the capacitance and effective load resistance

Hint:

Time constant $\tau = RC$ controls discharge speed.

Answer 1

Answer: (E)

Concept:
• Discharge of capacitor: \[ V \propto e^{-t/RC} \]

Step 1: Rate of fall
\[ \text{Rate} \propto \frac{1}{RC} \]

Step 2: Interpretation
Larger $RC$ → slower discharge
Smaller $RC$ → faster drop Final Conclusion:
Option (E)