Worked Examples

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8th Edition:
Homework Assignment #1:
problems: 1,7,9,11,13,14,27, 29, and
30.
1. Express each of the following numbers in scientific notation: (scientific notation
has only one digit to the left of the decimal point – the power of ten exponent
can be of any value)
a. 3000
b. 75,000
c. 2,000,000
3.0 x103
7.5 x104
2 x106
7. Express each of the following as a regular decimal number:
(Remember if the exponent sign is “+” move the decimal point to the right and if
it is “-“ move the decimal point to the left.)
a.
b.
c.
2.5 x10-6
5.0 x102
3.9 x10-1
0.0000025
500
0.39
9. Add the following numbers: (exponents must be the same value – adjust one of
the numbers to make it the same as the other.)
a.
(9.2 x106) + (3.4 x107) = (0.92 x107) + (3.4 x107) = 4.32 x107
I have found that converting the value that has the smaller exponent value to
match the larger value keeps the numbers more manageable.
b.
(5 x103) + (8.5 x10-1) = (5 x103) + (0.00085 x103) = 5.00085 x103
c.
(5.6 x10-8) + (4.6 x10-9) = (5.6 x10-8) + (0.46 x10-8) = 6.06 x10-8
11. Perform the following multiplications: (exponents are added to perform
multiplication)
a. (5 x103)(4 x105) = (5 x 4) x103+5 = 20 x108
b. (1.2 x1012)(3 x102) = (1.2 x 3) x1012+2 = 3.6 x1014
c. (2.2 x 10-9)(7 x10-6) = (2.2 x 7) x10-9+-6 = 15.4 x 10-15 = 1.54 x 10-14
13. Express each of the following numbers in Engineering Notation: (number to the
left of the decimal has to be between 1 and 999, with the exponent being a
multiple of 3. Remember to put power of ten notation into Metric prefixes)
a. 89,000 = 89,000 x100 = 89 x103 = 89k
b. 450,000 = 450,000 x100 = 450 x103 = 450k
c. 12,040,000,000,000 = 12,040,000,000,000 x100 = 12.04 x1012 = 12.04T
14. Express each of the following in engineering notation:
a. 2.35 x105 = 23.5 x104 = 235 x103 = 235k
b. 7.32 x107 = 73.2 x106 = 73.2M
c. 1.333 x109 = 1.333G (already in proper form)
27. Perform the indicated conversions: (First convert the prefix into power of ten
notation then if going from a larger exponent to a smaller one move the decimal
to the right; going from a smaller exponent to a larger one move the decimal to
the left.)
a. 5mA to microamperes ≈ 5 x10-3A = 5000 x10-6A =5000μA
b. 3200μW to milliwatts ≈ 3200 x10-6W = 3.2 x10-3W = 3.2mW
c. 5000kV to Megavolts ≈ 5000 x103V = 5 x106V = 5MV
d. 10MW to kilowatts ≈ 10 x106W = 10,000 x103W = 10,000kW
29. Add the following quantities: (First convert the prefixes into power of ten
notation; adjust so exponents are equal then add)
a. 50mA + 680 μA ≈ 50 x10-3A + 680 x10-6A = 50 x10-3A + 0.680 x 10-3A =
50.68 x10-3A = 50.68mA
(see calculator application)
b. 120kΩ + 2.2MΩ ≈ 120 x103Ω + 2.2 x106Ω = 0.12 x106Ω + 2.2 x106Ω =
2.32 x106Ω = 2.32MΩ
(see calculator application)
c. 0.02μF + 3300pF ≈ 0.02 x10-6F + 3300 x10-12F = 0.02 x10-6F + 0.0033
x10-6F = 0.0233 x10-6F = 23.3 x 10-9 = 23.3nF
(see calculator application)
30. Do the following operations: (convert metric prefixes into power of ten format;
note the use of parentheses to keep order of math operations)
a. 10kΩ / (2.2 kΩ + 10 kΩ)
10k Ω
10 × 103 Ω
10 × 103 Ω
⇒
=
= 0.8196721=
× 103−3 Ω 0.8196721
=
× 100 Ω 819.67=
× 10 −3 Ω 819.67m Ω
(2.2k Ω + 10K Ω)
(2.2 × 103 Ω + 10 × 103 Ω) 12.2 × 103 Ω
(see calculator application)
b. 250mV / 50μV
250mV
250 × 10 −3V
 250

5 × 10 −3+6V =
5 × 103V =
5kV
⇒
⇒
× 10( −3) −( −6)V  =
−6
50 µV
50 × 10 V
 50

(see calculator application)
c. 1MW / 2KW
1MW
1 × 106W
1

⇒
⇒  × 106 −3W  = 0.5 × 103W = 500W
3
2kW
2 × 10 W
2

(see calculator application)
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