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Question
In a parallel plate capacitor with air between the plates, each plate has an area of 6 × 10−3m2 and the separation between the plates is 3 mm.
- Calculate the capacitance of the capacitor.
- If this capacitor is connected to 100 V supply, what would be the charge on each plate?
- How would charge on the plates be affected, if a 3 mm thick mica sheet of k = 6 is inserted between the plates while the voltage supply remains connected?
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Solution
Here, A = 6 × 10–3m2, d = 3 mm = 3 × 10–3m
- Capacitance, C = `(∈_0A)/d`
= `((8.85 xx 10^-12 xx 6 xx 10^-3))/(3 xx 10^-3)`
= 17.7 × 10–12F - Charge, Q = CV
= 17.7 × 10–12 × 100
= 17.7 × 10–10C - New charge Q' = KQ
= 6 × 17.7 × 10–10
= 1.062 × 10–8C
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