ATILIM UNIVERSITY
ELECTRICAL AND ELECTRONICS ENGINEERING DEPARTMENT
EE 234 Introduction to Electrical Engineering
HOMEWORK 1
Date : 18th October 2024
DUE : 24th October 2024
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Q1 Determine the energy expended by a 24 V battery in moving 800x1018 electrons between
its terminals.
ANSW: Since E = Q × V and Q = number of electrons × charge of electrons
Then Q = [800×1018]×[1.6×10-19] = 128 C therefore E = 128 × 24 = 3072 J
Q2 If the energy above is expended in 10 seconds at a constant rate, what is the current
supplied by the battery?
ANSW: since P = E/T and E = 3072 then P = 3072/10 = 307.2 W
since P = 307.2 and P = V × I then I = P / V = 307.2 / 24 = 12.8 A
Q3 Write the color code of the following resistances and calculate the range of values they
may take in practice.
.
1.0 Mohm 5% tolerance
5.6 kohm 10% tolerance
2.2 ohm 10% tolerance
brown, black, green, gold
green, blue, red, silver
red, red, gold, silver
Q4) How much energy is stored in a 12 V 60 Ah battery?
AMSW: Since E = V × Q = 12 × 60 = 720 Wh
since 1 Wh = 3600 J then E = 720 × 3600 = 2.592 × 106 J
Q5) A house is supplied by DC 200V
This house consumes:
40 A for 2 hours
10 A for 4 hours
What is the maximum power required for this house?
ANSW: the maximum power will occur when the current is max so
Pmax = V × Imax = 200 × 40 = 8 × 103 W
What is the energy consumed in kWh in the 6 hour duration mentioned above.
ANSW: Since P = V × I
Then for the first 2h :
E1 = V × I × T = 200 × 40 × 2 = 16 kWh
For the second 4h :
E2 = V × I × T = 200 × 10 × 4 = 8 kWh
Then the total energy for the 6h duration :
Etotal = 8 + 16 = 24 kWh
Prof. Dr. H. Bülent Ertan