Magnets and Magnetic Fields + Work, Energy and Power Review + Waves and Sound Review
by Ulliyah Widayati
130 questions

Question 1

Use the bar-magnet field-line figure. At point P, the north end of a compass needle points along the field-line arrows. Which way does it point?

Accepted Answer

Toward the pole labeled S

Answer

Toward the pole labeled N

Answer

Perpendicular to the nearest field line

Answer

Opposite the field-line arrows

Question 2

In the field-line figure, point P is just outside the N pole. If a compass is placed at P, how does its north end orient?

Accepted Answer

Away from the N pole along the field line

Answer

Into the N pole along the field line

Answer

Toward the center of the bar no matter what the arrows show

Answer

At right angles to the field line

Question 3

Point P is just outside the S pole in the bar-magnet figure. Which compass orientation matches the magnetic field at P?

Accepted Answer

The needle's north end points into the S pole

Answer

The needle's north end points away from the S pole

Answer

The needle turns sideways because the field is zero at a pole

Answer

The needle's south end points along the arrows

Question 4

Look at point P below the middle of the bar magnet. A compass needle's north end points along the arrows. Which pole is it generally pointing toward?

Accepted Answer

The S pole

Answer

The N pole

Answer

Neither pole, because the field is zero below the middle

Answer

Both poles equally, so the needle has no direction

Question 5

In the two-magnet figure, point P lies in the gap. A compass needle's north end points along the field shown by the arrows. Which description is correct?

Accepted Answer

It points from the facing N pole toward the facing S pole

Answer

It points from the facing S pole toward the facing N pole

Answer

It points straight out of both facing poles at once

Answer

It points opposite the field-line arrows

Question 6

At point P above the gap in the attracting-magnets figure, how should the north end of a compass needle line up?

Accepted Answer

Tangent to the nearby field line in the arrow direction

Answer

Straight toward the nearest piece of metal regardless of arrows

Answer

Opposite the arrow direction because north repels north

Answer

Randomly, because two magnets cancel everywhere above the gap

Question 7

In the figure with two facing N poles, point P is near a field line leaving one pole. Which way does a compass north end point there?

Accepted Answer

Away from the nearby N pole along the line

Answer

Into the nearby N pole along the line

Answer

Toward the center of the gap no matter what the line does

Answer

Opposite the line's arrow direction

Question 8

Use the figure of two magnets with facing S poles. A compass is placed at P, on the field line that passes through it. Which way does its north end point?

Accepted Answer

Toward the nearby S pole along the line

Answer

Away from the nearby S pole along the line

Answer

Toward the other magnet's center regardless of arrows

Answer

Sideways to the field line

Question 9

The arrows are hidden in this bar-magnet figure. Using the labeled poles, which way should the outside field line through point P be directed?

Accepted Answer

From N toward S

Answer

From S toward N

Answer

Out of both poles and ending in space

Answer

Into both poles and stopping there

Question 10

A compass is placed at point P on a field line around a bar magnet. Which part of the compass needle points along the arrow shown at P?

Accepted Answer

The north end of the needle

Answer

The south end of the needle

Answer

The pivot at the center only

Answer

Neither end, because a compass points only to geographic north

Question 11

In the attracting-poles figure, point P is in the gap and the field-line arrows cross the gap. What compass direction matches the arrows at P?

Accepted Answer

From the N-facing end toward the S-facing end

Answer

From the S-facing end toward the N-facing end

Answer

Away from both facing ends equally

Answer

Perpendicular to the field-line arrows

Question 12

At point P beside the curved field line around the bar magnet, what is the best description of the magnetic field direction?

Accepted Answer

Along the curve toward the S pole

Answer

Along the curve toward the N pole

Answer

Straight through empty space, ignoring the curve

Answer

Opposite the direction a compass north end points

Question 13

The bar-magnet figure marks points A and B. Where is the magnetic field stronger?

Accepted Answer

At A, where the field lines are closer together near a pole

Answer

At B, because it is farther from the magnet

Answer

The same at A and B, because all field lines have equal strength

Answer

At neither point, because field lines show direction only

Question 14

Compare points A and B in the bar-magnet field diagram. Which statement about field strength is supported by the line spacing?

Accepted Answer

The field is stronger at A because the lines are more crowded there

Answer

The field is stronger at B because it is farther from the pole

Answer

The field is weaker at A because the lines curve more sharply there

Answer

The field is zero at both points unless a compass is present

Question 15

In the attracting-magnets figure, points A and B are marked. Where is the magnetic field strongest?

Accepted Answer

At A in the gap, where the field lines are closest together

Answer

At B far from the gap, where the field lines spread out

Answer

Equally at A and B, because the magnets are the same size

Answer

Nowhere, because opposite poles cancel their fields in the gap

Question 16

The poles are not marked in this two-magnet figure. What do the field-line arrows show about the two facing ends?

Accepted Answer

Both facing ends are north poles

Answer

Both facing ends are south poles

Answer

One facing end is north and the other is south

Answer

Neither facing end is a pole

Question 17

The poles are not marked in this two-magnet figure. What do the field-line arrows show about the two facing ends?

Accepted Answer

Both facing ends are south poles

Answer

Both facing ends are north poles

Answer

The left facing end is north and the right facing end is south

Answer

The facing ends have no poles because they repel

Question 18

The poles are not marked in this two-magnet figure. Use the field lines in the gap. What must be true of the facing poles?

Accepted Answer

They are opposite poles

Answer

They are both north poles

Answer

They are both south poles

Answer

They are not magnetic poles

Question 19

Use the bar-magnet figure with pole labels hidden. Which rule correctly identifies the north pole from the arrows?

Accepted Answer

The north pole is the end where outside field lines leave the magnet

Answer

The north pole is the end where outside field lines enter the magnet

Answer

The north pole is the end with the widest-spaced field lines

Answer

The north pole is always the physically larger end

Question 20

In the attracting-magnets figure, compare point A in the gap with point B outside the pair. Which field is larger in magnitude?

Accepted Answer

The field at A is larger because the lines are packed more closely there

Answer

The field at B is larger because it is outside both magnets

Answer

The fields are equal because both points are on field lines

Answer

The field at A is zero because opposite poles cancel completely

Question 21

What is a magnetic field?

Accepted Answer

A vector field around a magnet that gives the direction and strength of magnetic effects

Answer

A cloud of electric charge stored on the magnet's surface

Answer

A material layer that appears only when iron filings are present

Answer

A force that always points from south to north outside a magnet

Question 22

Which statement about magnetic field lines is correct?

Accepted Answer

They form continuous closed loops

Answer

They begin at a north pole and end forever at a south pole

Answer

They cross wherever two magnets have equal strength

Answer

They exist only inside ferromagnetic materials

Question 23

Outside a bar magnet, what is the conventional direction of magnetic field lines?

Accepted Answer

From the north pole toward the south pole

Answer

From the south pole toward the north pole

Answer

Away from both poles equally

Answer

Clockwise around every magnet

Question 24

What does the north end of a compass needle show when placed in a magnetic field?

Accepted Answer

The direction of the magnetic field at that point

Answer

The direction opposite the magnetic field at that point

Answer

Only the location of the nearest metal object

Answer

The strength of gravity at that point

Question 25

Which list contains common ferromagnetic materials?

Accepted Answer

Iron, cobalt, and nickel

Answer

Copper, aluminum, and glass

Answer

Wood, plastic, and rubber

Answer

Water, paper, and sand

Question 26

Which object is most likely to be strongly attracted to an ordinary bar magnet?

Accepted Answer

An iron nail

Answer

An aluminum drink can

Answer

A copper penny

Answer

A plastic ruler

Question 27

In a piece of iron, what is a magnetic domain?

Accepted Answer

A small region where the magnetic effects of many atoms point the same way

Answer

A single iron atom that has gained or lost extra electrons

Answer

The region around a magnet where iron filings collect

Answer

The end of a magnet where its north or south pole sits

Question 28

Why can an unmagnetized iron paperclip have little overall magnetic field?

Accepted Answer

Its domains are mostly randomly oriented, so their effects cancel

Answer

Its atoms contain no electrons with magnetic effects

Answer

It has only south poles and no north poles

Answer

Its field lines cannot pass through air

Question 29

What makes a permanent magnet different from a temporary induced magnet?

Accepted Answer

A permanent magnet retains its magnetic behavior for a long time

Answer

A permanent magnet has only one pole

Answer

A permanent magnet works only while touching iron

Answer

A permanent magnet is always made of charged plastic

Question 30

For a simple bar magnet, where is the magnetic field usually strongest?

Accepted Answer

Near the poles

Answer

Exactly halfway between the poles outside the bar

Answer

Only at the geometric center inside the bar

Answer

Everywhere around the magnet with equal strength

Question 31

Which interaction between magnetic poles is correct?

Accepted Answer

Like poles repel, and unlike poles attract

Answer

Like poles attract, and unlike poles repel

Answer

All poles attract because all magnets pull metals

Answer

North poles attract everything, while south poles repel everything

Question 32

Why is a magnet described as a magnetic dipole?

Accepted Answer

It has both a north pole and a south pole

Answer

It has two separate electric charges on its ends

Answer

It has two different masses at its ends

Answer

It can be split into one isolated north pole and one isolated south pole

Question 33

A north pole of one bar magnet is brought near the south pole of another. What happens?

Accepted Answer

They attract each other

Answer

They repel each other

Answer

They become nonmagnetic immediately

Answer

They charge each other and then separate

Question 34

Two north poles of bar magnets are pushed toward each other. What force interaction should you expect?

Accepted Answer

Repulsion between the magnets

Answer

Attraction between the magnets

Answer

No interaction because only south poles exert forces

Answer

A force caused by electric charging of the magnets

Question 35

A magnet attracts an unmagnetized iron tack. What is the best explanation?

Accepted Answer

The magnet induces magnetization in the tack so an unlike pole is nearest

Answer

The magnet gives the tack a permanent electric charge

Answer

The tack becomes hot enough to stick to the magnet

Answer

All metals are pulled equally strongly by any magnet

Question 36

A copper ring and an iron ring are both held near a refrigerator magnet. Which prediction best matches ordinary classroom observations?

Accepted Answer

The iron ring is attracted much more strongly than the copper ring

Answer

Both rings are attracted equally because both are metals

Answer

The copper ring is attracted much more strongly than the iron ring

Answer

Neither ring can interact with a magnetic field in any way

Question 37

A bar magnet is cut cleanly into two shorter pieces. What poles does each piece have?

Accepted Answer

Each piece has its own north pole and south pole

Answer

One piece has only a north pole and the other only a south pole

Answer

Both pieces lose all magnetic poles

Answer

Each piece has only north poles at both ends

Question 38

A permanent magnet is heated strongly and hammered several times. Why might it become weaker?

Accepted Answer

Thermal motion and shocks can disorder its magnetic domains

Answer

The magnet gains extra electrons that cancel its poles

Answer

The north pole melts away before the south pole

Answer

The field lines are cut into open pieces

Question 39

A steel screwdriver becomes magnetized after being stroked many times in one direction with a strong magnet. What changed inside the steel?

Accepted Answer

More magnetic domains became aligned

Answer

The steel gained a layer of electric charge

Answer

The steel atoms turned into copper atoms

Answer

The screwdriver lost one of its poles

Question 40

A bar magnet originally has N on the left and S on the right. It is cut across the middle, and the two cut faces are brought close in their original positions. What happens between the cut faces?

Accepted Answer

They attract because the new inner faces are opposite poles

Answer

They repel because both new inner faces are north poles

Answer

They do not interact because cutting removes magnetism

Answer

They attract because the pieces have become electrically charged

Question 41

A 0.75 kg ball is released from rest 3.0 m above the floor, and air resistance is negligible. Which relationship reaches its speed just before impact in the fewest steps?

Accepted Answer

mgh = 1/2 mv^2

Answer

W = Fd cos theta

Answer

P = W/t

Answer

v = v0 + at

Question 42

A rope pulls a sled 12 m across level snow with a 40 N force at 25 degrees above the direction of motion. Which relationship directly gives the rope's work on the sled?

Accepted Answer

W = Fd cos theta

Answer

W = mgh

Answer

P = W/t

Answer

KE = 1/2 mv^2

Question 43

A 900 kg car speeds up from 10 m/s to 18 m/s on a level road. Which relationship most directly gives the net work done on the car?

Accepted Answer

W_net = 1/2 m(v_f^2 - v_i^2)

Answer

W_net = mg(h_f - h_i)

Answer

W_net = F/d

Answer

W_net = P/t

Question 44

An elevator motor lifts a 500 kg elevator upward 8.0 m at constant speed in 16 s. Which relationship gives the motor's average power against gravity?

Accepted Answer

P = mgh/t

Answer

P = mg/t

Answer

P = 1/2 mv^2

Answer

P = Fd cos theta

Question 45

A sliding crate of mass m stops because friction acts over distance d. Which relationship gives the magnitude of the friction force if its starting speed is v_i?

Accepted Answer

f_k d = 1/2 mv_i^2

Answer

f_k = mv_i/d

Answer

f_k d = mv_i

Answer

f_k d = mgh

Question 46

A skateboarder coasts up a frictionless ramp and momentarily stops at height h above the start. Which relationship finds h from the starting speed v?

Accepted Answer

1/2 mv^2 = mgh

Answer

mv = mgh

Answer

P = mgh/t

Answer

W = Fd

Question 47

A crane raises a crate at constant speed through vertical distance h. Which relationship gives the work done by the cable on the crate?

Accepted Answer

W = mgh

Answer

W = 1/2 mv^2

Answer

W = mg/h

Answer

W = mgh/t

Question 48

A cart rolls down a hill with friction, starting from rest at height h and ending with speed v. Which relationship gives the internal energy generated?

Accepted Answer

E_int = mgh - 1/2 mv^2

Answer

E_int = 1/2 mv^2 - mgh

Answer

E_int = mgh + 1/2 mv^2

Answer

E_int = mgh/t

Question 49

A student writes, 'At the bottom of the roller coaster drop, the potential energy has been used up and is gone.' Which correction is best?

Accepted Answer

The energy has been transferred mostly to kinetic energy, so total energy is still conserved.

Answer

The energy is destroyed at the bottom, which allows the car to speed up.

Answer

The car keeps all its potential energy and gains kinetic energy from nothing.

Answer

Potential energy can only become sound energy on a roller coaster.

Question 50

A student says, 'If a bicycle's speed doubles, its kinetic energy doubles.' Which correction should replace that statement?

Accepted Answer

Its kinetic energy becomes four times as large because KE depends on speed squared.

Answer

Its kinetic energy stays the same because mass has not changed.

Answer

Its kinetic energy becomes half as large because speed is in the denominator.

Answer

Its kinetic energy doubles only if the bicycle is moving uphill.

Question 51

A student writes, 'Carrying a backpack along a level hallway does positive work on it because the backpack feels heavy.' What is the physics correction?

Accepted Answer

The upward support force does zero work because it is perpendicular to the horizontal displacement.

Answer

The support force does positive work equal to weight times hallway length.

Answer

The support force does negative work because the backpack moves forward.

Answer

The work equals the backpack's mass times the hallway length.

Question 52

A student says, 'Power and energy mean the same thing because both are measured in watts.' Which correction is right?

Accepted Answer

Energy is measured in joules, while power is the rate of energy transfer measured in watts.

Answer

Energy and power are identical, and both are measured in joules.

Answer

Power is measured in newtons because it is a force.

Answer

Energy is measured in watts only when motion is vertical.

Question 53

A student says, 'Friction destroys energy when a sliding box slows down.' Which correction is best?

Accepted Answer

Friction converts mechanical energy into internal energy, but total energy is conserved.

Answer

Friction converts internal energy into mechanical energy, so the box must speed up.

Answer

Friction removes mass from the box, which lowers its kinetic energy.

Answer

Friction has no effect on energy because it acts opposite motion.

Question 54

Two balls are dropped from the same height with negligible air resistance. A student says the heavier ball lands faster because it had more potential energy. What is the correction?

Accepted Answer

Both land with the same speed because mass cancels in mgh = 1/2 mv^2.

Answer

The heavier ball lands faster because its weight does more work per kilogram.

Answer

The lighter ball lands faster because it has less inertia.

Answer

Both land with zero kinetic energy because potential energy is used up.

Question 55

A student writes, 'When I push a box at constant speed, my work disappears because the box's kinetic energy does not change.' Which correction is right?

Accepted Answer

Your positive work is balanced by friction's negative work and is transferred to internal energy.

Answer

Your work is zero because constant speed always means no force is applied.

Answer

Your work becomes extra gravitational potential energy on a level floor.

Answer

Your work disappears because energy is not conserved when friction acts.

Question 56

Use the energy bar chart for a 2.0 kg cart. What is the cart's speed at point B?

Accepted Answer

4.5 m/s

Answer

3.2 m/s

Answer

20 J

Answer

6.3 m/s

Question 57

Use the energy bar chart. What gravitational potential energy is missing at point B?

Accepted Answer

16 J

Answer

8 J

Answer

18 J

Answer

30 J

Question 58

Use the energy bar chart for a 5.0 kg object. What is the object's height at point B? Take g = 9.8 m/s^2.

Accepted Answer

1.0 m

Answer

0.50 m

Answer

2.0 m

Answer

10 m

Question 59

Use the energy bar chart for a skateboarder. What internal energy is generated by point B?

Accepted Answer

200 J

Answer

0 J

Answer

300 J

Answer

900 J

Question 60

Use the energy bar chart for a 0.50 kg ball. What is the ball's speed at point B?

Accepted Answer

5.7 m/s

Answer

4.0 m/s

Answer

8.0 m/s

Answer

6.3 m/s

Question 61

Use the energy bar chart. How much energy has been dissipated into internal energy by point B?

Accepted Answer

4 J

Answer

8 J

Answer

12 J

Answer

24 J

Question 62

Use the energy bar chart for a 3.0 kg cart. What is the cart's speed at point B?

Accepted Answer

5.5 m/s

Answer

3.9 m/s

Answer

45 J

Answer

7.1 m/s

Question 63

Use the energy bar chart for a 2.0 kg object. What height above the zero level does point B represent? Take g = 9.8 m/s^2.

Accepted Answer

1.0 m

Answer

1.5 m

Answer

2.6 m

Answer

20 J

Question 64

A 60 kg student climbs stairs with a vertical height of 4.0 m in 5.0 s at a steady pace. Take g = 9.8 m/s^2. What is the student's average power against gravity?

Accepted Answer

470 W

Answer

118 W

Answer

2350 W

Answer

24 W

Magnets and Magnetic Fields + Work, Energy and Power Review + Waves and Sound Review

Ways to Play

Device Games: Students play on their phones

Blast Go

Zombie Escape

Avalanche

Maze Blast

Cave Climb

Blast Out

Mystery Auction

Tour Guide

Food Truck Rush

Tug of War

Alien Blast

Glacier Rush

Board Games: Teacher-led, projected to the class

Like what you see?

More like this

Magnets and Magnetic Fields + Work, Energy and Power Review + Waves and Sound Review

Ways to Play

Device Games: Students play on their phones

Blast Go

Zombie Escape

Avalanche

Maze Blast

Cave Climb

Blast Out

Mystery Auction

Tour Guide

Food Truck Rush

Tug of War

Alien Blast

Glacier Rush

Board Games: Teacher-led, projected to the class

Like what you see?

More like this

Bug Blast

BlastRace

BlastQuiz

BlastBoard

Seek & Destroy

Mystery Blast

Checkers

Texas Hold 'Em

Da Bomb

Castle Siege

Hot Potato

Market Mayhem

King of the Hill

Bank Heist

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