How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each?
- 1 ampere.
- 25.23 amperes.
- 1.11 amperes.
Explanation
For parallel lamps add conductances: three 6ohm give 3/6 = 0.5 S and two 5ohm give 2/5 = 0.4 S, totalling 0.9 S, so combined resistance = 1/0.9 = 1.111ohm. Current I = V/R = 28/1.111 ~ 25.2 A, matching the marked value.
Edigno_92 asking:
resistance, then use ohms law (I=V/R) to find the total current. It is a tricky calculation to do without a calculator, so round the total resistance up (to 1 ohms) then choose the nearest answer for I.
Community Comments (1)
M
markino87 Posts: 4 09.10.2012 / 12:38
all resistance are in parallel, thus the voltage applied on all resistance is the same 28v.
by doing V/R u find the current required on each resistance, applying the kirchoff law of current (Itot=sum of each resistance) u 'll find the current=25.23
by doing V/R u find the current required on each resistance, applying the kirchoff law of current (Itot=sum of each resistance) u 'll find the current=25.23
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