Answer:
0.23 s
Explanation:
First of all, let's find the time constant of the circuit:

where
is the resistance
is the capacitance
Substituting,

The charge on a charging capacitor is given by
(1)
where
is the full charge
we want to find the time t at which the capacitor reaches 90% of the full charge, so the time t at which

Substituting this into eq.(1) we find

Answer:
The mass of the copper is 3.00kg
Explanation:
Chemical Energy
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