## anonymous one year ago MEDALS N BECOMING A FAN 1.)Three resistors 2.5 Ω, 3.5 Ω and 4 Ω are connected in parallel. What is the equivalent resistance? 0.94 Ω 9.4 Ω 1.1 Ω 10 Ω 2.) How long would it take for 3.5 C of charge to pass through a cross-sectional area of a wire in which a current of 5 mA passes? 7 s 70 s 700 s 1428 s

1. anonymous

@SolomonZelman @ash2326

2. anonymous

@DanJS

3. anonymous

@Loser66

4. Loser66

Parallel circuit for resistors formula $$\dfrac{1}{R_{total}}= \dfrac{1}{R_1}+\dfrac{1}{R_2}+\dfrac{1}{R_3}$$

5. anonymous

0.94 Ω

6. anonymous

#2 is the one im really stuck on

7. Loser66

put them in to get $$\dfrac{1}{R_total} =\dfrac{1}{2.5}+\dfrac{1}{3.5}+\dfrac{1}{4}= \dfrac{131}{140}$$ hence $$R_{total}= \dfrac{140}{131}=1.06$$

8. Loser66

Actually, I forgot all of my physics knowledge hehehe... have to rely on others.

9. anonymous

1 Amp = 1 C/s. Therefore$I=\frac{ q }{ \Delta t }$You're given q and I, solve for delta t. Don't forget that I is given in mA. It must be converted to A.

10. anonymous

is it 70? @ospreytriple

11. anonymous

Not quite.$\Delta t = \frac{ q }{ I } = \frac{3.5\text{ C}}{0.005 \text{ A}} = ?$