Define (i) potential difference, (ii) capacitance.
A capacitor stores energy.
Describe an experiment to demonstrate that a capacitor stores energy. The ability of ... show full transcript
Worked Solution & Example Answer:Define (i) potential difference, (ii) capacitance - Leaving Cert Physics - Question 9 - 2009
Step 1
(i) the charge stored on each plate of the capacitor;
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Answer
To calculate the charge (q) stored on each plate of the capacitor, use the formula:
q=CV
Where:
C is the capacitance in farads (F)
V is the potential difference in volts (V)
Given:
C = 64 imes 10^{-6} F (converted from μF)
V = 2500 V
Substituting the values:
q=(64imes10−6)imes2500
Calculating that:
q=0.16C
Step 2
(ii) the energy stored in the capacitor;
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Answer
The energy (E) stored in the capacitor can be calculated using the formula:
E=21CV2
Substituting the values:
E=21×(64×10−6)×(2500)2
Calculating:
E=200J
Step 3
(iii) the average current that flows through the victim when the capacitor discharges in a time of 10 ms;
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Answer
To find the average current (I), use the formula:
I=tq
Where:
q = charge (0.16 C from part (i))
t = time in seconds (10 ms = 0.01 s)
Substituting the values:
I=0.010.16
Calculating:
I=16A
Step 4
(iv) the average power generated as the capacitor discharges;
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Answer
The average power (P) can be determined using:
P=tE
Where:
E = energy (200 J from part (ii))
t = time (10 ms = 0.01 s)
Substituting the values:
P=0.01200
Calculating:
P=20000W
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