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An Introduction to Physical Science

James T. Shipman, Jerry D. Wilson, Charles A. Higgins, Jr.

Chapter 8

Electricity and Magnetism - all with Video Answers

Educators

Chapter Questions

01:10

Problem 1

An object has one million more electrons than protons. What is the net charge of the object?

Supratim Pal
Supratim Pal
Numerade Educator
01:09

Problem 2

How many electrons make up one coulomb of charge? (Hint: $q=n e .$ )

Sima Sarker
Sima Sarker
Numerade Educator
00:55

Problem 3

What are the forces on two charges of $-1.0 \mathrm{C}$ and $+2.0 \mathrm{C}$, respectively, if they are separated by a distance of $3.0 \mathrm{m} ?$

Kayla Gephart
Kayla Gephart
Numerade Educator
00:32

Problem 4

Find the force of electrical attraction between a proton and an electron that are $5.3 \times 10^{-11} \mathrm{m}$ apart (the arrangement in the hydrogen atom). Compare this force to the gravitational force between these particles (see Chapter 3.5 ).

Kayla Gephart
Kayla Gephart
Numerade Educator
01:27

Problem 5

There is a net passage of $4.8 \times 10^{18}$ electrons by a point in a wire conductor in 0.25 s. What is the current in the wire?

Mirza Aslam Beig
Mirza Aslam Beig
Numerade Educator
01:41

Problem 6

A current of 1.50 A flows in a conductor for 6.5 s. How many electrons pass a given point in the conductor during this time?

Luis Rios
Luis Rios
Numerade Educator
01:03

Problem 7

To separate a $0.25-\mathrm{C}$ charge from another charge, $40 \mathrm{J}$ of work is done. What is the electric potential energy of the charge?

Abhishek Jana
Abhishek Jana
Numerade Educator
02:35

Problem 8

What is the voltage of the $0.25-$ C charge in Exercise 7 ?

Vishal Gupta
Vishal Gupta
Numerade Educator
01:57

Problem 9

If an electrical component with a resistance of $50 \Omega$ is connected to a $120-V$ source, then how much current flows through the component?

Vishal Gupta
Vishal Gupta
Numerade Educator
01:11

Problem 10

What battery voltage is necessary to supply 0.50 A of current to a circuit with a resistance of $30 \Omega ?$

Dave Kratz
Dave Kratz
Numerade Educator
00:40

Problem 11

A flashlight uses batteries that add up to $3.0 \mathrm{V}$ and has a power output of $0.50 \mathrm{W}$.
(a) How much current is drawn from the batteries?
(b) What is the effective resistance of the flashlight?

Mrinal Rana
Mrinal Rana
Numerade Educator
00:29

Problem 12

A car radio draws 0.25 A of current in the auto's 12 -V electrical system.
(a) How much electric power does the radio use?
(b) What is the effective resistance of the radio?

Manish Kumar
Manish Kumar
Numerade Educator
02:39

Problem 13

How much does it cost to run a 1500 -W hair dryer 30 minutes each day for a month ( 30 days) at a cost of $18 \mathrm{c}$ per $\mathrm{kWh}$ ?

Vishal Gupta
Vishal Gupta
Numerade Educator
04:02

Problem 14

A refrigerator using $1000 \mathrm{W}$ runs one-eighth of the time. How much does the electricity cost to run the refrigerator each month at $18 \mathrm{c}$ per $\mathrm{kWh}$ ?

Supratim Pal
Supratim Pal
Numerade Educator
00:47

Problem 15

A 24-$\Omega$ component is connected to a 12-$V$ battery. How much energy is expended per second?

Brandy Heflin
Brandy Heflin
Numerade Educator
View

Problem 16

In Exercise 15 , using the equation given in the chapter, you probably found the power in two steps. Show that $P=V^{2} / R,$ which requires only one step.

Eduard Sanchez
Eduard Sanchez
Numerade Educator
00:42

Problem 17

The heating element of an iron operates at $110 \mathrm{V}$ with a current of $10 \mathrm{A}$.
(a) What is the resistance of the iron?
(b) What is the power dissipated by the iron?

Netra Sharma
Netra Sharma
University of Wisconsin - Milwaukee
03:52

Problem 18

A 9.0-W LED light bulb is turned on. It has an operating voltage of $120 \mathrm{V}$.
(a) How much current flows through the bulb?
(b) What is the resistance of the bulb?
(c) How much energy is used each second?

Sri Datta Vikas Buchemmavari
Sri Datta Vikas Buchemmavari
Numerade Educator
02:30

Problem 19

Two resistors with values of $25 \Omega$ and $35 \Omega$, respectively, are connected in series and hooked to a
12-V battery.
(a) How much current is in the circuit?
(b) How much power is expended in the circuit?

Sheh Lit Chang
Sheh Lit Chang
University of Washington
01:49

Problem 20

Suppose the two resistors in Exercise 19 were connected in parallel. What would be (a) the current and (b) the power in this case?

Manish Kumar
Manish Kumar
Numerade Educator
05:24

Problem 21

A student connects a $10 \Omega$ and a $20 \Omega$ resistor in series and then connects the arrangement to a 24-$V$ dc source.
(a) What is the current in each resistor?
(b) What is the power expended by each resistor, respectively.

Vishal Gupta
Vishal Gupta
Numerade Educator
10:24

Problem 22

The student in Exercise 21 connects the two resistors in parallel.
(a) What is the current in each resistor?
(b) What is the power expended by each resistor, respectively.

Ren Jie Tuieng
Ren Jie Tuieng
Numerade Educator
04:58

Problem 23

A $20.0 \Omega$, a $40.0 \Omega$, and a $60.0 \Omega$ resistor in series are connected to a 12.0-V dc source.
(a) What is the current through each resistor?
(b) What is the voltage drop across each resistor?

Adithya Ramanujam
Adithya Ramanujam
Numerade Educator
04:58

Problem 24

A $20.0 \Omega$, a $40.0 \Omega$, and a $60.0 \Omega$ resistor in parallel are connected to a 12.0-V dc source.
(a) What is the current through each resistor?
(b) What is the voltage drop across each resistor?

Adithya Ramanujam
Adithya Ramanujam
Numerade Educator
02:46

Problem 25

A transformer has 600 turns on its primary and 200 turns on its secondary.
(a) Is it a step-up or a step-down transformer?
(b) If a voltage of $100 \mathrm{V}$ is applied to the primary and a current of 0.25 A flows in these windings, then what are the voltage output of the secondary and the current in the secondary?

Mayukh Banik
Mayukh Banik
Numerade Educator
02:46

Problem 26

A transformer has 300 turns on its secondary and 100 turns on its primary. The primary is connected to a 12-V source.
(a) What is the voltage output of the secondary?
(b) If 2.0 A flows in the primary coil, then how much current is there in the secondary coil?

Mayukh Banik
Mayukh Banik
Numerade Educator
00:39

Problem 27

A transformer with 1000 turns in its primary coil has to decrease the voltage from $4400 \mathrm{V}$ to $220 \mathrm{V}$ for home use. How many turns should there be on the secondary coil?

Mayukh Banik
Mayukh Banik
Numerade Educator
01:16

Problem 28

A power company transmits current through a 240,000-$V$ transmission line. This voltage is stepped down at an area substation to $40,000 \mathrm{V}$ by a transformer that has 900 turns on the primary coil. How many turns are on the secondary of the transformer?

Ajay Singhal
Ajay Singhal
Numerade Educator