Physics Electrostatics NUMS 2023
PMDC Verified Question 58 of 131
Q.175 While studying charging and discharging of a capacitor, RC = Resistance \( \times \) capacitance is known as?
A
Electrostatic constant
B
Time constant
C
Dielectric constant
D
Proportionality constant
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Time constant
1. Concept:

In any RC circuit, the mathematical product of the Resistor's resistance and the Capacitor's capacitance specifically dictates how rapidly the circuit responds to changes in voltage.

2. Formula:

$$ \tau = R \times C $$

3. Solution:

  • Because Ohm \( imes \) Farad perfectly yields Seconds, this product provides a physical metric for time.


  • This specific value (\( \tau \)) is formally titled the "Time Constant," marking the exact time required to charge to ~63% capacity.


4. Why other options are incorrect:

Dielectric constant (\( \epsilon_r \)) is an insulation property. Electrostatic constant (\( k \)) is used in Coulomb's Law.

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