A)Two identical resistors are connected in parallel across a 30-V battery, which supplies them with a total power of 7.0 W. While the battery is still connected, one of the resistors is heated so that its resistance doubles. The resistance of the other resistor remains unchanged. Find (a) the initial resistance of each resistor, and (b) the total power delivered to the resistors after one resistor has been heated.
B)You have three capacitors: C1 = 60 ìF, C2 = 48 ìF, and C3 = 36 ìF. Determine the maximum equivalent capacitance you can obtain by connecting two of the capacitors in parallel and then connecting the parallel combination in series with the remaining capacitor.
C)A 2.64-F and a 7.03-F capacitor are connected in series across a 30.0-V battery. A 7.44-F capacitor is then connected in parallel across the 2.64-F capacitor. Determine the voltage across the 7.44-F capacitor.
2 answers
100
A.
a. E^2/R = 7
30^2/R = 7
R = 128.6 ohms.
R1 = R2 = 2*128.6 = 257.2 ohms.
b. 1/R = 1/257 + 1/2*257 = 0.005837
R = 171 ohms.
P = E^2/R = 30^2/171 = 5.2 Watts.
a. E^2/R = 7
30^2/R = 7
R = 128.6 ohms.
R1 = R2 = 2*128.6 = 257.2 ohms.
b. 1/R = 1/257 + 1/2*257 = 0.005837
R = 171 ohms.
P = E^2/R = 30^2/171 = 5.2 Watts.