Physics Final Exam Review Part 1

Although electrons in metal move in haphazard directions at many times the speed of sound, the drift speed of electrons that compose electric current is A) A fraction of a centimeter per second B) The speed of light C) Many centimeters per second

A) A fraction of a centimeter per second

Surrounding every stationary electron is A) An electric field B) A magnetic field C) Both of these D) Neither of these

A) An electric field

In an electrically neutral atom the number of protons in the nucleus is equal to the number of A) Electrons that surround the nucleus B) Both electrons and neutrons C) Neutrons in the nucleus C) None of the above

A) Electrons that surround the nucleus

Power is transmitted at high voltages because the corresponding current in the wires is A) Low so that overlapping of the wires is minimized B) Also high to deliver appreciable power to distant C) Choices A and B are true D) Choices A and B are false

A) Low so that overlapping of the wires is minimized

Rub electrons from your hair with a comb and the comb becomes A) Negatively Charged B) Discharged C) Positively Charged

A) Negatively Charged

Two lamps, one with a thick filament and one with a thin filament, are connected in series. The voltage is greater across the lamp with the A) Thin filament B) Thick filament C) The same in each lamp

A) Thin filament

Receiving an electric shock is much more dangerous when your skin is wet because A) Wet skin reduces the body's resistance to electric current B) Wet skin multiplies voltage C)Water converts direct current to alternating current D) Water attracts electric charge

A) Wet skin reduces the body's resistance to electric current

In the unlikely case of a lightning strike, it is worse to be inside a building framed with A) Wood B) Iron C) Aluminum D) Steel

A) Wood

An iron core in a transformer A) Separates the primary and secondary regions B) Guides the magnetic field lines C) Shields unwanted external electric or magnetic fields D) Reduces energy losses

B) Guides the magnetic field lines

The power dissipated in a 4-ohm resistor carrying 3 A is A) 48 W B) 36 W C) 2.25 W D) 5.33 W

B) 36 W

Direct Current is normally produced by A) Generator B) Battery C) Both of these D) Neither of these

B) Battery

You can touch a 100,000-volt Van de Graff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small amount of A) Polarization B) Energy C) Electric field D) Conduction

B) Energy

Connect a pair of lamps in series and currents is drawn from the battery. Connect the same lamps in parallel and the current drawn is. A) Less B) More C) The same D) Sometimes more, sometimes less

B) More

The force on an electron moving in a magnetic field will be the largest when its direction is A) At and angle other than 90 degrees to the magnetic field direction B) Perpendicular to the magnetic field direction C) Exactly opposite to the magnetic field direction D) The same as the magnetic field direction

B) Perpendicular to the magnetic field direction

As the number of loops in a current-carrying wire is increased, the A) Greater the back emf B) Stronger the enclosed magnetic field C) More spread out is the magnetic field D) Weaker the current

B) Stronger the enclosed magnetic field

An iron rod becomes magnetic when A) Its atoms are aligned having plus charges on one side and negative charges on the other B) The domains of the aligned spinning electrons are aligned with each other in the same direction C)It's electrons stop moving and point in the same direction

B) The domains of the aligned spinning electrons are aligned with each other in the same direction

The energy dissipated in a light bulb in a circuit is provided by the A) lamp filament itself B) Voltage source C) Wires leading to the lamp D) None of the above

B) Voltage source

About how much resistance does a standard light bulb have? A) 2 ohms B) 2000 ohms C)200 ohms D)20000 ohms E)20 ohms

C) 200 ohms

Two charges that are separated by one meter exert 1-N forces on each other. If the magnitude of each charge is doubled, the force on each charge is A) 1 N B) 8 N C) 4 N D) 2 N E) None of the above

C) 4 N

If we think of the earth as a magnet, its magnetic south pole is nearest A) Australia B) The Hudson bay region of Canada C) Both of these

C) Both of these

The primary purpose of a lightning rod is to A) Induce a charge opposite to that of a charged clouds overhead B) Cancel the electric field within the structure to which it is attached C) Discharge the structure to which it is attached D) Attract lightning and guide it to the ground

C) Discharge the structure to which it is attached

The headlights, radio, and defroster fan in an automobile are connected in A) Parallel without separate switches B) Series with a switch for each C) Parallel with a switch for each D) Series without separate switches

C) Parallel with a switch for each

Insulating materials are composed of atoms with A) Vastly more charge than conductors B) Excess protons C) Tightly bound outer electrons D) Weak cohesive force

C) Tightly bound outer electrons

To say that electric charge is quantized is to say that the charge on an object A) Can be neither created or destroyed B) Is sometimes positive C)Is a whole-number multiple of the charge of one electron D) Will interact with the neighboring electric charge

C)Is a whole-number multiple of the charge of one electron

An electron is pushed into an electric field where it acquires a 1-V electrical potential. If two electrons are pushed the same distance into the same electric field, the electrical potential of the two electrons is A).25 V B) 4 V C) .5 V D) 1 V

D) 1 V

When a 10-V battery is connected to a resistor, the current in the resistor is 2 A. What is the resistor's value? A) 20 ohms B) 10 ohms C)5 ohms D) 2 ohms E) More than 20 ohms

D) 2 ohms

Voltage can be induced in a wire by A) Moving the wire near a magnet B) Changing the current in a nearby wire C) Moving a magnet near the wire D) Choices A, B, C are all true E) None of the choices above are true

D) Choices A,B,C are all true

To say that an object is electrically polarized is to say A) Its internal electric field is zero B) It is electrically charged C) It is to some degree magnetic D) Its charges have been rearranged

D) Its charges have been rearranged

A device that transforms electrical energy to mechanical energy is a A) Generator B) Transformer C) Magnet D) Motor E) None of these

D) Motor

Four amperes of current exist in the primary coil of a transformer. The voltage across the primary coil is 120 V. What is the power output of the secondary coil? A) 120 W B) 30 W C) 3600 W D) 480 W E) Need more information

D)480 W

It is correct to say that in electric circuits A) Voltage is the ratio of energy per charge B) Charge flows through a circuit C) Flowing charge in current D) Voltage is applied across a circuit E) All of the above

E) All of the above