Download PHYS 1260 Exam 1 Dewitt |1260 Final Exam Compiled| 259 Latest Questions And Answers Graded and more Exams Physics in PDF only on Docsity!
PHYS 1260 Exam 1 Dewitt | 1260 Final Exam
Compiled| 259 Latest Questions And Answers
Graded A+
Just as gravity is the study of a wide range of gravitational interactions, electricity is the study of a wide range of A) electrical charges. B) electrical forces. C) electrical interactions. D) [none of these]
- Correct Answer C Electrostatics is a branch of electricity that focuses on A) electrical charge. B) electrical force. C) both of these when static. D) [none of these]
- Correct Answer C 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) neutrons in the nucleus C) both electrons and neutrons. D) [none of these]
- Correct Answer A The pair of protons in the nucleus of a helium atom A) attract a pair of orbiting electrons. B) repel orbiting electrons. C) [both of these] D) [neither of these]
- Correct Answer A Two protons attract each other gravitationally and repel each other electrically. The stronger of these two forces is A) gravitation. B) electrical. C) [neither of these]
- Correct Answer B The unit of electric charge, the coulomb, is the charge on a A) single electron. B) specific large number of electrons.
The electrical force on a 2-C charge is 60 N. The electric field where the charge is located is A) 20 N/C. B) 30 N/C. C) 60 N/C. D) 120 N/C. E) 240 N/C.
- Correct Answer B The electric field between oppositely-charged parallel plates is A) uniform. B) stronger at the ends. C) composed of field lines in opposite directions. D) [none of these]
- Correct Answer A Electric potential, measured in volts, is the ratio of electrical potential energy to the amount of electric A) current. B) resistance. C) charge. D) voltage.
E) [none of these]
- Correct Answer C If 10 J of work is used in pushing a 1-C charge into an electric field, its electric potential relative to its starting position is A) less than 10 V. B) 10 V. C) more than 10 V. D) [none of these]
- Correct Answer B To think of electric potential difference we are thinking about A) current. B) voltage. C) resistance.
- Correct Answer B An ampere is a unit of electric A) current. B) voltage. C) resistance.
- Correct Answer A
- Correct Answer C The current produced by voltage in a circuit is impeded by A) electric barriers. B) closed switches. C) electric resistance. D) [none of these]
- Correct Answer C Ohm's law tells us that the amount of current produced in a circuit is A) directly proportional to voltage. B) inversely proportional to resistance. C) [both of these] D) [neither of these]
- Correct Answer C Current in a conductor can be increased by A) increasing the voltage across it. B) reducing its resistance. C) [both of these] D) [neither of these] - Correct Answer C
22.1. What term is used for "electricity at rest"? - Correct Answer Electrostatics is the term for electricity at rest 22.2. Which part of an atom is positively charged, and which part is negatively charged? - Correct Answer The nucleus and its protons are positively charged; the electrons are negatively charged 22.2. What is most commonly the net charge of an atom? - Correct Answer The normal net charge is zero 22.3. What is meant by the conservation of charge? - Correct Answer Conservation of charge means that charge cannot be created or destroyed, but merely transferred. 22.3. Name one particle that has exactly one quantum unit of charge? - Correct Answer An electron (or proton) has exactly one quantum unit of charge. 22.4. How is Coloumb's Law similar to Newton's law of gravitation? How is it different? - Correct Answer Both laws are inverse-square laws. The main difference is that gravitation is only attractive, whereas electrical forces can repel
22.9. A balloon may easily be charged to several thousand volts. Does that mean it has several thousand joules of energy? Explain. - Correct Answer No. Several thousand volts is different from the ratio several thousand volts per coulomb. Voltage is measured in volts; voltage/coulomb is energy and measured in joules. Several thousand joules per coulomb isn't much energy if you have a tiny fraction of a coulomb 23.1. What condition is necessary for the flow of heat? What analogous condition is necessary for the flow of charge? - Correct Answer Heat must have a difference in temperature. Charge must have a difference in electric potential 23.1. Why are electrons, rather than protons, the principle charge carriers in metal wire? - Correct Answer Electrons in metals are free to wander, whereas protons are imbedded in atomic nuclei, not free to roam 23.2. Name two kinds of practical "electrical pumps". - Correct Answer One kind is a battery; another is a generator 23.2. Does electric charge flow across a circuit or through a circuit? Does voltage flow across or is it impressed across? - Correct Answer Electric charge flows through a circuit. Voltage doesn't flow at all but is impressed across a circuit
23.3. Does heating a metal wire increase or decrease its electrical resistance? - Correct Answer Heating a metal wire increases molecular motion and therefore its electrical resistance 23.4. If the voltage impressed across a circuit is held constant while the resistance doubles, what change occurs in the current? - Correct Answer When the resistance doubles, the current is halved 23.4. How does wetness affect the resistance of your body? - Correct Answer Wetness lowers your body's electrical resistance
- Electricity - Correct Answer A general term for electrical phenomena, much like gravity has to do with gravitational phenomena, or sociology with social phenomena.
- Electrostatics - Correct Answer The study of electric charge at rest (not in motion, as in electric currents).
- Conservation of charge - Correct Answer Electric charge is neither created nor destroyed. The total charge before an interaction equals the total charge after
- Electrically polarized - Correct Answer The term applied to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge
- Electric field - Correct Answer Electrical force per unit of charge. The field can be considered to be an "aura" surrounding charged objects and is a storehouse of electric energy. About a charged point, the field decreases with distance according to the inverse-square law, like a gravitational field. Between oppositely charged parallel plates, the electric field is uniform: EF = F/q
- Electric potential energy - Correct Answer The energy a charged object possesses by virtue of its location in an electric field.
- Electric potential - Correct Answer The electric potential energy per unit of charge, measured in volts; often called voltage: V = electric potential energy / charge
- Capacitator - Correct Answer An electrical device—in its simplest form, a pair of parallel conducting plates separated by a small distance—that stores electric charge and energy
When two lamps are connected in series to a battery, the electrical resistance that the battery "senses" is a) more than the resistance of either lamp b) less than the resistance of either lamp c) none of these - Correct Answer a When two lamps are connected in parallel to a battery, the electrical resistance that the battery "senses" is a) more than the resistance of either lamp b) less than the resistance of either lamp c) none of these - Correct Answer b On some early automobiles both headlights failed when one bulb burned out. The headlights were likely connected in a) parallel b) perpendicular c) series d) haste - Correct Answer c Magnet A has twice the magnetic field strength of Magnet B and at a certain distance pulls on magnet B with a force of 100 N. The amount of force that magnet A exerts on magnet B is
a) a magnetic field b) an electric field c) both of these d) none of these - Correct Answer b Surrounding every moving electron is a) a magnetic field b) an electric field c) both of these d) none of these - Correct Answer c (this magnetic field is a result of distortions in the electric field caused by the motion of the electron) The shape of a magnetic field surrounding a current-carrying conductor is a) consistent with the inverse-square law b) radial c) circular d) all of these e) neither of these - Correct Answer c The direction of the force exerted on a moving charge in a magnetic field is a) in the direction of the motion b) opposite its motion
c) at right angles to the direction of the motion - Correct Answer c When a change occurs in the magnetic field in a closed loop of wire a) a voltage is induced in the wire b) a current is created in the loop of the wire c) electromagnetic induction occurs d) all of these e) none of these - Correct Answer d When a magnet is moved to and fro in a wire coil, voltage is induced. If the coil has twice as many loops, the voltage induced is a) half b) the same c) twice d) four times as much e) none of these - Correct Answer c The frequency of induced voltage in a wire coil depends on a) the frequency of current producing it b) how frequently a magnet dips in and out of the coil c) the number of loops in the coil - Correct Answer b
- Alternating current (ac) - Correct Answer Electrically charged particles that repeatedly reverse direction, vibrating about relatively fixed positions. In the United States, the vibrational rate is commonly 60 Hz.
- Electric power - Correct Answer The rate of energy transfer, or the rate of doing work; the amount of energy per unit time, which can be computed as the product of current and voltage: Power = current * voltage Electric power is measured in watts (or kilowatts)
- Series circuit - Correct Answer An electric circuit in which electrical devices are connected along a single loop of wire such that the same current is in each device
- Parallel circuit - Correct Answer An electric circuit in which electrical devices are connected in such a way that the same voltage acts across each one, and any single one completes the circuit independently of all the others. 24.1. By whom, and in what setting, was the relationship between electricity and magnetism discovered? - Correct Answer Hans Christian Oersted in a high- school classroom noted how a current affects a magnet, thus relating electricity and magnetism
24.1. What is the source of magnetic force? - Correct Answer Moving electrons are the source of magnetic force. 24.2. In what way are magnetic poles very different from electric charges? - Correct Answer Magnetic poles cannot be isolated; electric charges can 24.3. What produces a magnetic field? - Correct Answer The motion of electric charges produces a magnetic field. 24.5. In Chapter 22, we learned that the direction of the electric field about a point charge is radial to the charge. What is the direction of the magnetic field surrounding a current-carrying wire? - Correct Answer The magnetic field takes the form of concentric circles about a current-carrying wire 24.5. Why is the magnetic field strength greater inside a current carrying loop of wire than about a straight section of wire? - Correct Answer Inside the loop the lines are more concentrated 24.7. In what direction relative to a magnetic field does a charged particle move in order to experience maximum deflecting force? Minimum deflecting force? - Correct Answer Force is maximum when motion is perpendicular to the field; minimum when parallel to the field
