A parallel-plate capacitor is connected to a battery and stores 3.6 nC of charge
ID: 1499016 • Letter: A
Question
A parallel-plate capacitor is connected to a battery and stores 3.6 nC of charge. Then, while the battery remains connected, a sheet of Teflon is inserted between the plates. For the dielectric constant, use the value from Table 21.3. Does the capacitor's charge increase or decrease? The capacitor's charge increases. The capacitor's charge decreases. The capacitor's charge remains the same. It's impossible to determine. By how much does the charge change? Express your answer with the appropriate units.Explanation / Answer
let the battery has emf of = V volts
so charge stored
Q1 = CV
V = Q1/C
now after dielectric capacitance will change
C2 = kC
so new charge Q2 = C2 V
Q2 = (kC) * Q1/C
Q2 = kQ1
Q2 = 2.1 * 3.6 nC { we know that for teflon dielectric k = 2.1}
Q2 = 7.56 nC
1) the capacitor charge will increase
2) change in charge = Q2-Q1
= (7.56 - 3.6 ) nC
= 3.96 C
answer