Physics practice exam 2023

A lever is used to lift a 225-kg crate 3.2 m up to the bed of a truck. The lever is 82 percent efficient. How much work needs to be done on the lever in order to lift the crate? a. 8600 J b. 7100 J c. 5800 J d. 1300 J

8600

A/An _____ is described as a low resistance device connected in series that is used to measure current. a. ammeter b. circuit breaker c. fuse d. voltmeter

Ammeter

Which of the following statements is true about electric forces? a. Electric forces cause objects to only attract each other. b. Electric forces cause objects to only repel each other. c. Electric forces cause objects to repel or attract each other. d. Electric forces do not cause objects to affect each other.

Electric forces cause objects to repel or attract each other.

_____ is described as the sum of all the individual resistances in a series. a. Equivalent resistance b. Parallel circuit c. Series circuit d. Short circuit

Equivalent resistance

A circuit breaker is a short piece of metal that melts when a current that is too large passes through it

False

A series connection is a type of electric circuit in which there are multiple paths

False

Two points are equipotential if their electric potential difference is greater than zero.

False

One kilowatt-hour is equal to the energy transformed by an electric device of 1 W for 1 hour (T/F)

False, 1000 watt for 1 hour

Which of the following is true for the direction of an electric field? a. It is same as the direction of the force exerted on a negative test charge. b. It is opposite to the direction of the force exerted on a positive test charge. c. It is same as the direction of the force exerted on a positive test charge. d. It is opposite to the direction of the force exerted on a neutral test charge

It is same as the direction of the force exerted on a positive test charge.

A(n)_____ is equal to the amount of energy that a 1,000-W device transforms in 3,600 s. a. battery b. electric current c. ampere d. Kilowatt-hour

Kilowatt-hour

_____charges repel, whereas _____ charges attract. a. Like, opposite b. Opposite, like c. Positive, negative d. Negative, positive

Like, opposite

Charges added on one part of an insulator remain on that part (T/F)

True

Like charges repel, whereas opposite charges attract.

True

Resistance is a property that determines the current in a circuit.

True

The law of conservation of momentum states that the momentum of a closed, isolated system does not change.

True

To measure the potential drop across a resistor, a voltmeter is connected in parallel with a resistor.

True

Voltmeters are designed to have a very high resistance so as to cause the smallest possible change in currents andvoltages in the circuit.

True

The relationship between linear acceleration and angular acceleration is given by: a. v = d/t b. a = rα c. v = rω d. d = rθ

a = rα

Which conditions will result in the smallest change in momentum? a. a large force over a long time period b. a large force over a short time period c. a small force over a long time period d. a small force over a short time period

a small force over a short time period

A hair dryer with a resistance of 12.0 and a lamp with a resistance of 125 are connected in parallel to a 125-V source through a 1.50- resistor in a series. Find the current through the lamp when the hair dryer is on. a. 0.880 A b. 8.80 A c. 88.0 A d. 880 A

a. 0.880 A

_____ are strongest near the sharp points of sharply pointed conductors. a. Electric fields b. Electric field lines c. Capacitors d. Electric potential differences

a. Electric fields

A series circuit consists of a switch, a 6-V battery, a lightbulb, and some copper wire. Whenever the circuit is turned on, each of these elements has the same a. current through it. b. potential difference across it. c. resistance in it. d. Temperature.

a. current through it.

A(n) _____ is described as a closed loop or pathway that allows electric charges to flow. a. electric circuit b. conventional current c. parallel connection d. series connection

a. electric circuit

A/An _____ is described as the flow of charged particles. a. electric field b. electric potential difference c. electric current d. gravitational force

a. electric field

A/An _____ is a unit of energy, whereas a _____ is equal to one joule per coulomb. a. joule, volt b. volt, joule c. joule, newton d. volt, newton

a. joule, volt

The unit _____ is used to measure electric potential energy; whereas the unit _____ is used to measure electric potential difference. a. joule, volt b. volt, joule c. newton, volt d. newton, joule

a. joule, volt

An area with excess electrons has a net _____ charge; an area with a deficit of electrons has a net _____ charge. a. negative, positive b. positive, negative c. positive, neutral d. negative, neutral

a. negative, positive

A/An _____ is described as the flow of electric charge or current equal to one coulomb per second. a. volt b. capacitor c. capacitance d. ampere

ampere

The current equal to one coulomb per second is a/an _____. a. ampere b. kilowatt hour c. ohm d. volt

ampere

Electric forces can be either repulsive or attractive, whereas gravitational force is always: a. attractive b. repulsive c. both a and b d. neither a nor b

attractive

The direction of the force on a positive test charge near another positive charge is _____ the other charge. a. away from b. toward c. parallel to d. perpendicular

away from

Electric field lines are directed _____ positive charges and _____ negative charges. a. away from, toward b. toward, away from c. parallel to, perpendicular to d. perpendicular to, parallel to

away from, toward

The distance between two charges qa and qb is r, and the force between them is F. What is the force between them if the distance between them is doubled? a. F/4 b. 4F c. 9F d. F/9

b. 4F

Whenever the electric potential difference between two or more positions is zero, those positions are said to be _____. a. equal b. equipotential c. in equilibrium d. in parallax

b. equipotential

A(n) _____ is an energy unit that power companies use to measure electrical energy use. a. ampere b. kilowatt-hour c. ohm d. Volt

b. kilowatt-hour

What is the effect on the current in a simple circuit when both the voltage and the resistance are divided by 2? a. divided by 2 b. no change c. multiplied by 2 d. multiplied by 4

b. no change

Which is not a simple machine? a. pulley b. ramp c. bicycle d. wood screw

bicycle

Three rods of different materials P, Q, and R, are charged by various methods. When the rods are brought near each other, the rods P and Q repel each other, while the rods P and R attract each other. Which of the following could be the signs of the charges on the rods? Rod P Rod Q Rod R a. - + - b. - + - c. - - + d. - - -

c. - - +

A car battery causes a current of 2.0 A through a lamp and produces 12 V across it. What is the power used by the lamp? a. 0.167 W b. 6 W c. 24 W d. 48 W

c. 24 W

42. The diagram above illustrates the electric field lines between three equally spaced objects. What could be the charges on those objects? a. A+, B-, C- b. A+, B+, C+ c. A-, B-, C+ d. A+, B-, C+

d. A+, B-, C+

Which is not a part of the walking mechanism of the human body? a. a rigid bar b. a fulcrum c. a resistance d. a gear

d. a gear

The relationship between linear displacement and angular displacement is given by: a. v = d/t b. a = rα c. v = rω d. d = rθ

d. d = rθ

When a test charge is used to measure the electric field around a charged object, the test charge must be very small, primarily so that it a. is not significantly affected by the electric field of Earth. b. is not significantly affected by the gravitational pull of Earth. c. does not exert an electric force strong enough to move the charged object. d. does not exert a gravitational force strong enough to move the charged object.

does not exert an electric force strong enough to move the charged object.

A/An _____ is the field that exists around any charged object. a. electric field line b. electric potential difference c. gravitational force d. electric field

electric field

Machines make tasks easier by changing either the magnitude or the direction of the _____ needed. a. force b. work c. energy d. Velocity

force

A short piece of metal that melts when a large current passes through it is a: a. circuit breaker b. surge suppressor c. relay d. fuse

fuse

If the work done in moving a charge is doubled and the strength of the charge is halved, the electric potential difference: a. increases to four times its original value. b. decreases to half its original value. c. increases to twice its original value. d. decreases to one-fourth of its original value.

increases to twice its original value.

A/An _____ is described as a type of circuit in which there is only a single current path. a. parallel circuit b. series circuit c. short circuit d. voltage divider

series circuit

A/An _____ is described as a series circuit that is used to produce a lower voltage from a higher voltage battery. a. parallel circuit b. series circuit c. short circuit d. voltage divider

voltage divider

How much energy does it require to move a constant positive charge of 2.0 C through a potential difference of 3.0 V? a. 6.0 J b. 0.0 J c. 1.5 J d. 3.0 J

6.0 J

A car panel lamp has a resistance of 33 ω when it is placed across a 12 V battery. What is the current through the circuit? a. 0.36 A b. 2.8 A c. 3.96 A d. 396 A

0.36 A

A radian is a unit of measurement equal to _____. a. 1/400 of a revolution b. 1/360 of a revolution c. 1/(2π) of a revolution d. 1/4 of a revolution

1/(2π) of a revolution

What has a larger capacitance, an aluminum sphere with a 10 cm diameter or one with a 100 cm diameter? a. 10 cm b. 100 cm c. They are both the same. d. cannot be determined

100cm

A parallel circuit has four branch currents: 120 mA, 380 mA, 250 mA, and 2.1 A. How much current is supplied by the source? a. .029 A b. 0.29 A c. 2.9 A d. 29 A

2.9 A