1. Based on the figure below, if the source of electromotive force (emf) is 24 Volt, determine electric current I.
Known :
Source of emf = 24 Volt
Internal resistance (r) = 2 Ohm
Resistor 40 Ohm, 20 Ohm, and 20 Ohm.
Wanted : Electric current I
Solution :
Resistors connected in parallel, the equivalent resistor :
1/R = 1/40 + 1/20 + 1/20
1/R = 1/40 + 2/40 + 2/40
1/R = 5/40
R = 40/5
R = 8 Ohm
Terminal voltage :
V = emf – I r
V = 24 – I 2
Electric current I :
V = I R
24 – I 2 = I 8
24 = I 8 + I 2
24 = I (10)
I = 24/10
I = 2.4 Ampere
[irp]
2. Based on figure below, if R1 = 3 Ω, R2 = 4 Ω, R3 = 4 Ω and electric current is 0.5 A. Determine electric voltage.
Known :
Electric current (I) = 0.5 Ampere
Resistor R1 = 3 Ohm
Resistor R2 = 4 Ohm
Resistor R3 = 4 Ohm
Wanted : Electric voltage (V)
Solution :
Calculate the equivalent resistance :
R2 and R3 are connected in parallel. The equivalent resistor :
1/R23 = 1/R2 + 1/R3 = 1/4 + 1/4 = 2/4
R23 = 4/2 = 2 Ohm
R1 and R23 are connected in series. The equivalent resistor :
R = R1 + R23 = 3 + 2 = 5 Ohm
Electric voltage :
V = I R = (0.5)(5) = 2.5 Volt
[irp]