More resistor questions?

Question

A 2.00- resistor and a 12.0- resistor are connected in a parallel across a 20.0-V battery. What is the current flowing through the 2.00- resistor?

A. 1.67 A

B. 1.40 A

C. 11.6 A

D. 10.0 A

A 15.0- resistor and a 20.0- resistor are connected in a parallel. A 5.00- resistor is connected across a 1.00 10^2-V battery. What is the current flowing through the 20.0- resistor?

A. 1.21 A

B. 3.15 A

C. 5.00 A

D. 6.84 A

A 2.0-V battery is connected in a curcuit with an ammeter and an unknown resistor, P. The current is observed to be 0.70 A. What would be the current in the curcuit if a 12-V battery replaces the 2.0-V battery?

A. 4.2 A

B. 6.0 A

C. 8.4 A

D. 34 A

Thanks for the help! Sorry the many questions but, I need em so, thanks!

Answer 1

A 2.00- resistor and a 12.0- resistor are connected in a parallel across a 20.0-V battery. What is the current flowing through the 2.00- resistor?

I = E/R =20v/2 ohms = 10 amps

A 15.0- resistor and a 20.0- resistor are connected in a parallel. A 5.00- resistor is connected across a 1.00 10^2-V battery. What is the current flowing through the 20.0- resistor?

If the 5 ohm resistor is connected across the 100 volt battery you will get 20 amps. but it's not, and you need to say how it is connected.

A 2.0-V battery is connected in a curcuit with an ammeter and an unknown resistor, P. The current is observed to be 0.70 A. What would be the current in the curcuit if a 12-V battery replaces the 2.0-V battery?

R = E/I = 2/0.7 = 2.86 ohms

I = E/R = 12/2.86 = 4.2 amps

You can also do this by knowing that current is proportional to voltage. Increase voltage by 6 times, current increases by 6 times, and I = 0.7*6 = 4.2 amps.

Answer 2

why don't you do your own homework?

E=I/R