Answer:
90 μF
Explanation:
C' = Capacitance of charged capacitor = 30 x 10⁻⁶ F
[tex]V_{initial}[/tex] = initial potential difference across the plates = 80 V
[tex]V_{finall}[/tex] = final potential difference across the plates = 20 V
Q = Charge stored by unknown capacitance
Charge stored by unknown capacitance is given as
Q = C' ([tex]V_{initial}[/tex] - [tex]V_{finall}[/tex])
Q = (30 x 10⁻⁶) (80 - 20)
Q = 1.8 x 10⁻³ C
C = Capacitance of unknown capacitor
V = Potential difference across the plates of unknown capacitor = 20
Charge stored by unknown capacitor is given as
Q = CV
1.8 x 10⁻³ = C (20)
C = 90 x 10⁻⁶ F
C = 90 μF
