this current splits. Since R 1 is twice R 2 , half as much current will flow through R 1
as through R 2 ; the current through R 1 is I 1 = 2 A, and the current through R 2 is I 2 = 4
A. The voltage drop across each of these resistors is I 1 R 1 = I 2 R 2 = 1,200 V
(matching voltages verify the values of currents I 1 and I 2 ). Since the ammeter is in
the branch that contains R 2 , it will read I 2 = 4 A.
The voltmeter will read the voltage drop across R 3 , which is V 3 = IR 3 = (6 A)(150
Ω) = 900 V. So the potential at point b is 900 V lower than at point a.
- The following diagram shows a point a at potential V = 20 V
connected by a combination of resistors to a point (denoted G) that
is grounded. The ground is considered to be at potential zero. If
the potential at point a is maintained at 20 V, what is the current
through R 3?
Here’s How to Crack It
R 1 and R 2 are in parallel; their equivalent resistance is RP, where