Question

Current 1 of 8.4 A runs for 240 seconds and then stops. Current 2 is 10.5 A.

How long does current 2 have to run to deliver the same amount of charge as current 1?

88.2 s
192 s
2016 s
21,000 s

Answer 1

To find out how long current 2 (10.5 A) needs to run to deliver the same amount of charge as current 1 (8.4 A) did in 240 seconds, we first calculate the charge delivered by current 1.

The charge \( Q \) is given by the formula:

\[
Q = I \times t
\]

where \( I \) is the current and \( t \) is the time.

For current 1:
\[
Q_1 = 8.4 \, \text{A} \times 240 \, \text{s} = 2016 \, \text{C}
\]

Now we need to find the time \( t_2 \) that current 2 has to run to deliver the same charge of 2016 C.

For current 2:
\[
Q_2 = 10.5 \, \text{A} \times t_2
\]

Setting \( Q_1 \) equal to \( Q_2 \):
\[
2016 \, \text{C} = 10.5 \, \text{A} \times t_2
\]

Now we can solve for \( t_2 \):
\[
t_2 = \frac{2016 \, \text{C}}{10.5 \, \text{A}} \approx 192 \, \text{s}
\]

Thus, current 2 needs to run for approximately **192 seconds** to deliver the same amount of charge as current 1 did.

So, the answer is:
**192 s**.