I worked out that 20mA = 20000A and 30 minutes = 1800s and I=Q/t
So that means Q=It = 20000 x 1800 = 360000000 C
My friends say i am wrong, can you please help me?
2006-10-02 18:53:06 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
mA stands for milliampere, or 1/1000th of an ampere. One ampere = 1 coulomb/second. So if you have a conductor carrying a 20 mA current for 30 minutes, the total charge passing through that conductor during that time is:
Q = (20/1000 * C/s) * 60 sec/min * 30 min = 36 coulombs.
2006-10-02 19:00:47 · answer #1 · answered by hfshaw 7 · 0⤊ 0⤋
20 mA = .02 A, not 20000 A.
(you're confusing milliamps with kiloamps; DIVIDE by 1000, not multiply)
take it from there, and re-do your calculations.
2006-10-03 01:55:56 · answer #2 · answered by Glenn 2 · 0⤊ 0⤋
20ma = 0.020A
30 minutes = 1800sec
now,
I = dQ / dt =>
dQ = I * dt = 0.020 * 1800 = 36Cb
(36000 Cb would have been two much out of logic when only 20mA are available)
2006-10-03 01:59:27 · answer #3 · answered by Emmanuel P 3 · 1⤊ 0⤋
20 mA is 0.02 A, which results in 36 C.
2006-10-03 01:57:12 · answer #4 · answered by arbiter007 6 · 0⤊ 0⤋