Energy may be measured in: A cylindrical copper rod has resistance R. It is refo
ID: 2300126 • Letter: E
Question
Energy may be measured in:
A cylindrical copper rod has resistance R. It is reformed to half of its original length with no change of volume. Its new resistance is:
A 60 watt light bulb carries a current of 0.5A. The total energy consumed in ten hours is:
Two 110-V light bulbs, one 25W and the other 100W are connected in series to a 110W source. Then:
Four 20 ohm resistors are connected in parallel and the combination is connected to a 20 V emf device. The current in any one of the resistors is:
please show work if not numerical just explain reasoning behind answer thank you
Explanation / Answer
1) electron volts
2) V1 = V2
A1 * L1 = A2 * L2
A2/A1 = L1/L2 = 2
R2/R1 = (L2/L1)*(A1/A2) = 1/2 * 1/2 = 1/4
Thus, final resistance = R/4
3) Energy consumed = 60/1000 * 10 = 0.6 kWh
4) current will be the same in both, one with higher voltage will grow brighter/
Thus, none of the above is correct option
5) Total resistance = 20/4 = 5 ohm
Total current = 20/5 = 4 A
Current in each resistor = 4/4 = 1.0 A
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