Applied Physics

Dale Ewen, Neill Schurter, Erik Gundersen

Chapter 17

Basic Electricity - all with Video Answers

Educators

MA

Chapter Questions

Problem 1

Two charges, each $-4.50 \mu \mathrm{C}$, are $0.150 \mathrm{cm}$ apart. Find their repulsive force.

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Problem 2

The repulsive force between two identical negative charges is $0.750 \mathrm{N}$ when they are $0.100 \mathrm{m}$ apart. Find the amount of each charge.

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Problem 3

A charge of $2.50 \times 10^{-8} \mathrm{C}$ exerts a force of $0.0250 \mathrm{N}$ on a second charge of $5.00 \times 10^{-7} \mathrm{C} .$ How far apart are the charges?

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Problem 4

A positive test charge of $2.50 \mu \mathrm{C}$ is placed in an electric field. The force on it is $0.500 \mathrm{N} .$ What is the magnitude of the electric field at the location of the test charge?

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Problem 5

Find the magnitude of the electric field in which a negative charge of $1.50 \times 10^{-8} \mathrm{C}$ experiences a force $\mathrm{pf} 9.0590 \mathrm{N}$

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Problem 6

What force is exerted on a test charge of $4.25 \times 10^{-5} \mathrm{C}$ if it is placed in an electric field of magnitude $2.50 \times 10^{4} \mathrm{N} / \mathrm{C} ?$

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Problem 7

Find the resistance of $85.5 \mathrm{m}$ of No. 20 aluminum wire $\left(\rho=2.83 \times 10^{-6} \Omega \mathrm{cm},\right.$ $\left.A=2.07 \times 10^{-2} \mathrm{cm}^{2}\right)$

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Problem 8

At $75^{\circ} \mathrm{F}, 120 \mathrm{ft}$ of wire has a resistance of $0.743 \Omega .$ Find the resistance of $560 \mathrm{ft}$ of this wire.

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Problem 9

Find the resistance of 134 m of No. 20 copper wire at $20^{\circ} \mathrm{C}\left(\rho=1.72 \times 10^{-6} \Omega \mathrm{cm},\right.$, $\left.A=2.07 \times 10^{-2} \mathrm{cm}^{2}\right)$

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Problem 10

Find the length of a copper wire with resistance $0.0273 \Omega / \mathrm{ft}$ and total resistance $3.97 \Omega$.

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Problem 11

Find the cross-sectional area of copper wire at $20^{\circ} \mathrm{C}$ that is $55.4 \mathrm{m}$ long and has resistivity $\rho=1.79 \times 10^{-6} \Omega \mathrm{cm}$ and resistance $0.943 \Omega$

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Problem 12

A heating element operates on 115 V. If it has a resistance of $15.4 \Omega,$ what current does it draw?

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Problem 13

A heating coil operates on $220 \mathrm{V}$. If it draws $8.75 \mathrm{A}$, find its resistance.

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Problem 14

What current does a $234-\Omega$ resistance draw on 115 V?

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Problem 15

Four resistors of $3.40 \Omega, 6.54 \Omega, 8.32 \Omega,$ and $1.34 \Omega$ are connected in series with a $12.0-\mathrm{V}$ battery. Find the total resistance of the circuit.

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Problem 16

Find the current in Problem $15 .$

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Problem 17

Find the emf in the circuit shown in Fig. 17.76 .

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Problem 18

Find the equivalent resistance in the circuit shown in Fig. 17.77 .

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Problem 19

Find $R_{3}$ in the circuit in Problem 18 .

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Problem 20

Find the equivalent resistance in the circuit shown in Fig. 17.78 .

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Problem 21

Find the current in Fig. 17.78 .

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Problem 22

Find the current through $R_{1}$ in Fig. 17.78 .

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Problem 23

Find the current through $R_{2}$ in Fig. 17.78 .

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Problem 24

Find the equivalent resistance in the circuit of Fig. $17.79 .$

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Problem 25

Find the current through $R_{3}$ in Fig. 17.79 .

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Problem 27

Find the equivalent resistance in Fig. 17.80 .

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Problem 28

Find the current in $R_{5}$ in Fig. 17.80 .

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Problem 29

Find the voltage drop across $R_{5}$ in Fig. 17.80 .

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Problem 30

Find the current in $R_{1}$ in Fig. 17.80 .

Umar Sohail Qureshi

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Problem 31

Find the voltage drop across $R_{1}$ in Fig. 17.80 .

Umar Sohail Qureshi

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Problem 32

Using the formulas for series and parallel circuits, fill in the blanks in the table below for the circuit of Fig. 17.81

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Matty Anderson

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Problem 33

A cell has an emf of $1.44 \mathrm{V}$ and an internal resistance of $0.0550 \Omega .$ If there is $0.135 \mathrm{A}$ in the cell, what voltage is applied to the external circuit?

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Problem 34

The voltage applied to a circuit is $12.0 \mathrm{V}$ when the current through the battery is 0.858 A. If the internal resistance of the battery is $0.245 \Omega,$ what is the emf?

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Problem 35

Six 6.00-V cells, each with an internal resistance of 0.0987 $\Omega$ and current output of $0.658 \mathrm{A},$ are connected in parallel to form a battery in a certain circuit. (a) What is the current in the external circuit? (b) What is the emf of the battery? (c) What is the internal resistance of the battery?

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Problem 36

Find the current in the circuit shown in Fig. 17.82 .

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Problem 37

Find the total resistance in the circuit shown in Fig. 17.83 .

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Problem 38

What power is needed for a drill that draws $2.45 \mathrm{A}$ and has a resistance of $6.55 \Omega$ on a $110-\mathrm{V}$ circuit?

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Problem 39

How many amperes will a $15 \overline{0}$ - $W$ light bulb draw on a $11 \overline{0}$ - $V$ circuit?

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Problem 40

What is the cost to operate the lamp in Problem 39 for 135 h if the cost of energy is $\$ 0.05 / \mathrm{kWh} ?$

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Problem 41

If the cost of energy is $\$ 0.043 / \mathrm{kWh},$ how long could you operate a motor that draws $0.40 \mathrm{A}$ on a $110-\mathrm{V}$ line for $\$ 0.45 ?$

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Problem 42

How many amperes will a $10\overline0-\mathrm{W}$ lamp draw on a $110-\mathrm{V}$ line?

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