Rheostat is used in the experiment, and it has to be set to the maximum value before the switch is closed, why is it so?
2007-03-04 23:42:13 · 3 answers · asked by highupthesky 1 in Science & Mathematics ➔ Physics
Because the charge that builds up on the capacitor is directly related to the resistance. The charge is given by:
Q = Qo[1 - e^(-t/RC)]
That exponent is the reason.
2007-03-04 23:57:43 · answer #1 · answered by Biznachos 4 · 0⤊ 0⤋
Because the rate of charging (i.e. current) is given by
I = U/R = (Ub - Uc)/R, where Ub and Uc are the
voltages of the battery and the capacitor.
Initially Uc = 0, and R must be the largest if you want
constant current.
2007-03-05 05:21:17 · answer #2 · answered by Alexander 6 · 0⤊ 0⤋
gonna take a guess and say time constant RC
2007-03-04 23:55:46 · answer #3 · answered by John 5 · 0⤊ 0⤋