Question 1

If undisturbed, an electric current in a superconducting wire loop

Accepted Answer

A)  will decrease to a stop in a few seconds. 
B)  will decrease to a stop in a day or two. 
C)  will continue indefinitely. 
D)  will gradually increase. 
A)  will decrease to a stop in a few seconds. 
B)  will decrease to a stop in a day or two. 
C)  will continue indefinitely. 
D)  will gradually increase. C

Question 2

A drawing of the field lines of a magnetic field provides information on

Accepted Answer

A)  the direction of the field only. 
B)  the strength of the field only. 
C)  both the direction and the strength of the field. 
D)  the source of the field. 
A)  the direction of the field only. 
B)  the strength of the field only. 
C)  both the direction and the strength of the field. 
D)  the source of the field. C

Question 3

Two charges, one positive and the other negative, are initially 2 cm apart and are then pulled away from each other until they are 8 cm apart. The force between them is now smaller by a factor of

Accepted Answer

A)  2. 
B)  4. 
C)  16. 
D)  32. 
A)  2. 
B)  4. 
C)  16. 
D)  32. C

Question 4

The voltage needed to produce a current of 8 A in a resistance of 12 ohms is

Accepted Answer

A)  0.67 V. 
B)  1.5 V. 
C)  4 V. 
D)  96 V. 
A)  0.67 V. 
B)  1.5 V. 
C)  4 V. 
D)  96 V.

Question 5

The power rating of an electric motor that draws a current of 3 A when operated at 240 V is

Accepted Answer

A)  80 W. 
B)  720 W. 
C)  1080 W. 
D)  2160 W. 
A)  80 W. 
B)  720 W. 
C)  1080 W. 
D)  2160 W.

Question 6

When a current passes through a resistance, the electric energy that is lost

Accepted Answer

A)  becomes heat. 
B)  becomes magnetic energy. 
C)  is returned to the source of the current. 
D)  disappears. 
A)  becomes heat. 
B)  becomes magnetic energy. 
C)  is returned to the source of the current. 
D)  disappears.

Question 7

An object has a positive electric charge whenever

Accepted Answer

A)  it has an excess of electrons. 
B)  it has a deficiency of electrons. 
C)  the nuclei of its atoms are positively charged. 
D)  the electrons of its atoms are positively charged. 
A)  it has an excess of electrons. 
B)  it has a deficiency of electrons. 
C)  the nuclei of its atoms are positively charged. 
D)  the electrons of its atoms are positively charged.

Question 8

When the voltage across a certain resistance is V, the power delivered is P. If the voltage is halved to V/2, the power delivered becomes

Accepted Answer

A)  P/2. 
B)  P/4. 
C) 
  
D) 
 
)
/4) 
A)  P/2. 
B)  P/4. 
C) 
  
D) 
 
)
/4)

Question 9

Two charges repel each other with a force of 10-6 N when they are 10 cm apart. When they are brought closer together until they are 2 cm apart, the force between them becomes

Accepted Answer

A)  4 × 10-8 N. 
B)  5 ×10-6 N. 
C)  8 × 10-6 N. 
D)  2.5 × 10-5 N. 
A)  4 × 10-8 N. 
B)  5 ×10-6 N. 
C)  8 × 10-6 N. 
D)  2.5 × 10-5 N.

Question 10

A kilowatt hour is a unit of

Accepted Answer

A)  energy. 
B)  power. 
C)  potential difference. 
D)  electric charge. 
A)  energy. 
B)  power. 
C)  potential difference. 
D)  electric charge.

Question 11

Which of the following statements is not true?

Accepted Answer

A)  Protons are positively charged. 
B)  The proton mass is greater than the electron mass. 
C)  The proton mass is almost the same as the neutron mass. 
D)  A proton in an atom circulates around its nucleus. 
A)  Protons are positively charged. 
B)  The proton mass is greater than the electron mass. 
C)  The proton mass is almost the same as the neutron mass. 
D)  A proton in an atom circulates around its nucleus.

Question 12

A negative electric charge

Accepted Answer

A)  interacts only with positive charges. 
B)  interacts only with negative charges. 
C)  interacts with both positive and negative charges. 
D)  may interact with either positive or negative charges, depending on circumstances. 
A)  interacts only with positive charges. 
B)  interacts only with negative charges. 
C)  interacts with both positive and negative charges. 
D)  may interact with either positive or negative charges, depending on circumstances.

Question 13

Superconductivity occurs in certain substances

Accepted Answer

A)  only at very low temperatures. 
B)  only at very high temperatures. 
C)  at all temperatures. 
D)  only when they are in the liquid state. 
A)  only at very low temperatures. 
B)  only at very high temperatures. 
C)  at all temperatures. 
D)  only when they are in the liquid state.

Question 14

A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is

Accepted Answer

A)  parallel to the field. 
B)  perpendicular to the field. 
C)  either parallel or perpendicular, depending on the direction of the current. 
D)  at a 45-degree angle with the field. 
A)  parallel to the field. 
B)  perpendicular to the field. 
C)  either parallel or perpendicular, depending on the direction of the current. 
D)  at a 45-degree angle with the field.

Question 15

Atoms and molecules are normally

Accepted Answer

A)  electrically neutral. 
B)  negatively charged. 
C)  positively charged. 
D)  ionized. 
A)  electrically neutral. 
B)  negatively charged. 
C)  positively charged. 
D)  ionized.

Question 16

A molecule that has lost an electron becomes a

Accepted Answer

A)  positive ion. 
B)  negative ion. 
C)  nucleus. 
D)  superconductor. 
A)  positive ion. 
B)  negative ion. 
C)  nucleus. 
D)  superconductor.

Question 17

Direct electric current cannot be used to operate

Accepted Answer

A)  electric motors. 
B)  electric heaters. 
C)  electromagnets. 
D)  transformers. 
A)  electric motors. 
B)  electric heaters. 
C)  electromagnets. 
D)  transformers.

Question 18

An electric iron draws a current of 15 A when connected to a 120-V power source. Its resistance is

Accepted Answer

A)  0.125 ohms. 
B)  8 ohms. 
C)  16 ohms. 
D)  1800 ohms. 
A)  0.125 ohms. 
B)  8 ohms. 
C)  16 ohms. 
D)  1800 ohms.

Question 19

Which of the following statements is not true?

Accepted Answer

A)  The positive charge in an atomic nucleus is due to the protons it contains. 
B)  All protons have the same charge. 
C)  Protons and electrons have charges equal in magnitude although opposite in sign. 
D)  Protons and electrons have equal masses. 
A)  The positive charge in an atomic nucleus is due to the protons it contains. 
B)  All protons have the same charge. 
C)  Protons and electrons have charges equal in magnitude although opposite in sign. 
D)  Protons and electrons have equal masses.

Question 20

The nucleus of an atom

Accepted Answer

A)  contains most of the atom's mass. 
B)  is nearly as large as the atom. 
C)  is electrically neutral. 
D)  may contain protons, neutrons, and electrons. 
A)  contains most of the atom's mass. 
B)  is nearly as large as the atom. 
C)  is electrically neutral. 
D)  may contain protons, neutrons, and electrons.

If undisturbed, an electric current in a superconducting wire loop

A drawing of the field lines of a magnetic field provides information on

Two charges, one positive and the other negative, are initially 2 cm apart and are then pulled away from each other until they are 8 cm apart. The force between them is now smaller by a factor of

The voltage needed to produce a current of 8 A in a resistance of 12 ohms is

The power rating of an electric motor that draws a current of 3 A when operated at 240 V is

When a current passes through a resistance, the electric energy that is lost

An object has a positive electric charge whenever

When the voltage across a certain resistance is V, the power delivered is P. If the voltage is halved to V/2, the power delivered becomes

Two charges repel each other with a force of 10^-6 N when they are 10 cm apart. When they are brought closer together until they are 2 cm apart, the force between them becomes

A kilowatt hour is a unit of

Which of the following statements is not true?

A negative electric charge

Superconductivity occurs in certain substances

A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is

Atoms and molecules are normally

A molecule that has lost an electron becomes a

Direct electric current cannot be used to operate

An electric iron draws a current of 15 A when connected to a 120-V power source. Its resistance is

Which of the following statements is not true?

The nucleus of an atom

The Scientific Method

Motion

Energy

Energy and the Future

Matter and Heat

Waves

The Nucleus

The Atom

The Periodic Law

Crystals, Ions, and Solutions

Chemical Reactions

Organic Chemistry

Atmosphere and Hydrosphere

The Rock Cycle

The Evolving Earth

The Solar System

The Stars

The Universe Galaxies

Filters

Exam 6: Electricity and Magnetism

If undisturbed, an electric current in a superconducting wire loop

A drawing of the field lines of a magnetic field provides information on

Two charges, one positive and the other negative, are initially 2 cm apart and are then pulled away from each other until they are 8 cm apart. The force between them is now smaller by a factor of

The voltage needed to produce a current of 8 A in a resistance of 12 ohms is

The power rating of an electric motor that draws a current of 3 A when operated at 240 V is

When a current passes through a resistance, the electric energy that is lost

An object has a positive electric charge whenever

When the voltage across a certain resistance is V, the power delivered is P. If the voltage is halved to V/2, the power delivered becomes

Two charges repel each other with a force of 10-6 N when they are 10 cm apart. When they are brought closer together until they are 2 cm apart, the force between them becomes

A kilowatt hour is a unit of

Which of the following statements is not true?

A negative electric charge

Superconductivity occurs in certain substances

A current-carrying loop in a magnetic field always tends to turn until the plane of the loop is

Atoms and molecules are normally

A molecule that has lost an electron becomes a

Direct electric current cannot be used to operate

An electric iron draws a current of 15 A when connected to a 120-V power source. Its resistance is

Which of the following statements is not true?

The nucleus of an atom

The Scientific Method

Motion

Energy

Energy and the Future

Matter and Heat

Waves

The Nucleus

The Atom

The Periodic Law

Crystals, Ions, and Solutions

Chemical Reactions

Organic Chemistry

Atmosphere and Hydrosphere

The Rock Cycle

The Evolving Earth

The Solar System

The Stars

The Universe Galaxies

Filters

Two charges repel each other with a force of 10^-6 N when they are 10 cm apart. When they are brought closer together until they are 2 cm apart, the force between them becomes