physics DC circuits [EZ +10]?

B

Bugz

New member
In the circuit above, R1 = 1870 Ohm, R2 = Rm = 8.9 Ohm and V = 6.6 volts.

A) Calculate the current I coming out of the battery without R2 in the circuit. Express your units as "mA".

C) Calculate the ratio of IB/IA

B) Calculate the current I coming out of the battery with R2 in the circuit. Express your units as "mA".

Diagram: http://img67.imageshack.us/i/circuitdiagram2.jpg/

I keep getting .00351mA for part A
and .00702 mA for part B and it says its wrong.

A very quick explanation would be appreciated. I'm probably just making a stupid mistake somewhere. This should be really easy.
 
A

AlP

New member
A)
IA = V/R = 6.6/(1870+8.9) = 3.51269359731758E-03 A
IA = 3.513 ma

B)
R2 and Rm are now in parallel:
IB = V/R = 6.6/(1870+(8.9/2)) = 3.52103283629865E-03 A
IB = 3.521 ma

C)
IB/IA = 1.002277
 
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