Multiple-Choice

Chapter 19: DC Circuits

 

1)  When current flows to an external circuit, the potential difference between the terminals of a

     battery, is referred to as the  

 

     A) emf.

     B) terminal voltage.

     Answer: B

 

2)  Assume that no current flows to an external circuit. In this case the potential difference between

     the terminals of a battery is referred to as the  

     A) emf.

     B) terminal voltage.

     Answer: A

 

3)  When two or more resistors are connected in series to a battery

 

     A) the total voltage across the combination is the algebraic sum of the voltages across the   

         individual resistors.

     B) the same current flows through each resistor.

     C) the equivalent resistance of the combination is equal to the sum of the resistances of each

          resistor.

     D) all of the answers are correct

     Answer: D

 

4)  When you connect resistors in series,

 

     A) the same power is dissipated in each resistor.

     B) the potential difference across each resistor is the same.

     C) the current flowing in each resistor is the same.

     D) More than one of the given answers is true.

     Answer: C

 

5)  Assume that three identical resistors are connected in series to a battery.  If the current of 12 A

     flows from the battery, how much current flows through the second resistor?

 

     A) 12 A

     B) 4 A

     C) 36 A

     D) zero

     Answer: A

 

6)  When two or more resistors are connected in parallel to a battery,

 

     A) the voltage across each resistor is the same.

     B) the total current flowing from the battery equals the sum of the currents flowing through each

         resistor.

     C) the equivalent resistance of the combination is less than the resistance of any one of the

         resistors.

     D) all of the given answers

     Answer: D

 

7)  When resistors are connected in parallel, we can be certain that

 

     A) the same current flows in each one.

     B) the potential difference across each is the same.

     C) the power dissipated in each is the same.

     D) their equivalent resistance is greater than the resistance of any one of the individual

         resistances.

     Answer: B

 

8)  Three identical resistors are connected in series to a 12-V battery.  What is the voltage across the

      second resistor?

 

     A) 36 V

     B) 12 V

     C) 4 V

     D) zero

     Answer: C

 

9)  Assume that you have a 100-W light bulb and a 50-W light bulb.  Instead of connecting them in the

     normal way, you devise a circuit that places them in series across normal household voltage (120

     volts).  Which of the following statements is correct?

 

     A) Both bulbs glow at the same reduced brightness.

     B) Both bulbs glow at the same increased brightness.

     C) The 100-W bulb glows brighter than the 50-W bulb.

     D) The 50-W bulb glows more brightly than the 100-W bulb.

     Answer: D

 

10)  Kirchhoff's loop rule is an example of

 

       A) conservation of energy.

       B) conservation of charge.

       C) conservation of momentum.

       D) none of the given answers

       Answer: A

 

11)  Kirchhoff's junction rule is an example of

 

       A) conservation of energy.

       B) conservation of charge.

       C) conservation of momentum.

       D) none of the given answers

       Answer: B

 

Multiple-Choice

Chapter 20: Magnetism

 

1)  If a bar magnet is divided into two equal pieces,

  

     A) the north and south poles are separated.

     B) two magnets result.

     C) the magnet properties are destroyed.

     D) an electric field is created.

     Answer: B

 

2)  The Earth's geographic North Pole is magnetically a  

 

    A) north pole.        B) south pole.         Answer: B

 

3)  An electric current produces  

 

     A) a gravitational field.

     B) an electric field.

     C) a magnetic field.

     D) an electromagnetic field.

     Answer: C

 

4)  The SI unit of magnetic field is the

 

     A) weber.

     B) gauss.

     C) tesla.

     D) lorentz.

     Answer: C

 

5)  1 T is equivalent to

 

     A) 1 N∙m/A.

     B) 1 N∙A/m.

     C) V∙m/A.

     D) N/A∙m.

     Answer: D

 

6)  The direction of the force on a current-carrying wire in a magnetic field is described by which of the

     following?

 

     A) perpendicular to the current only

     B) perpendicular to the magnetic field only

     C) perpendicular to both the current and the magnetic field

     D) perpendicular to neither the current or the magnetic field

     Answer: C

 

7)  The force on a current-carrying wire in a magnetic field is the strongest when  

     A) the current is parallel to the field lines.

     B) the current is at a 30° angle with respect to the field lines.

     C) the current is at a 60° angle with respect to the field lines.

     D) the current is perpendicular to the field lines.

     Answer: D

 

8)  A charged particle moves and experiences no magnetic force.  From this we can conclude that

 

     A) no magnetic field exists in that region of space.

     B) the particle is moving parallel to the magnetic field.

     C) the particle is moving at right angles to the magnetic field.

     D) either no magnetic field exists or the particle is moving parallel to the field.

     Answer: D

 

9)  A charged particle moves across a constant magnetic field.  The magnetic force on this particle

 

     A) changes the particle's speed.

     B) causes the particle to accelerate.

     C) is in the direction of the particle's motion.

     D) changes the particle's speed causing the particle to accelerate.

     Answer: B

 

10)  A charged particle is observed traveling in a circular path in a uniform magnetic field.  If the

       particle had been traveling twice as fast, the radius of the circular path would be

 

       A) twice the original radius.

       B) four times the original radius.

       C) one-half the original radius.

       D) one-fourth the original radius.

       Answer: A

 

11)  A particle carrying a charge of +e travels in a circular path in a uniform magnetic field.  If instead

       the particle carried a charge of +2e, the radius of the circular path would have been

 

       A) twice the original radius.

       B) four times the original radius.

       C) one-half the original radius.

       D) one-fourth the original radius.

       Answer: C

 

Extra Credit

Identify the individual described - last name only

 

1)  While building electromagnets,________________________________discovered the

     electromagnetic phenomenon of self-inductance. He also discovered mutual inductance

     independently of Michael Faraday, though Faraday was the first to publish his results.   

     Henry

 

2)  With only three months of formal education ____________________became one of the greatest

     inventors and industrial leaders in history. He obtained 1,093 United States patents.  Edison

 

3)  A current produced by an induced emf moves in a direction so that its magnetic field opposes the

     original change in flux is a statement of ___________________________ law.  Lenz's

 

4)  _____________ was born in what is today Croatia and later became an American citizen.   After his demonstration of wireless communication through radio in 1894 and after being the victor in the "War of Currents", he was widely respected as one of the greatest electrical engineers in America. Tesla

   

5)  He was a French physicist and military engineer. In his 1824 Reflections on the Motive Power of

     Fire, he gave the first successful theoretical account of heat engines, thereby laying the

     foundations of the second law of thermodynamics. The _________________ cycle is named after

     him. Carnot