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Physical Science Final Exam

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PHSC1100 Dr. Tavossi's Class. Fall 2014.
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Question 1

Question
The International System of Units, SI Units, or metrics units of: length, mass, and time are:
Answer
  • m, kg, min
  • m, kg, h
  • ft, slug, s
  • m, kg, s
  • cm, g, s

Question 2

Question
The power in SI-Unit is measured in Watt, that is related to energy by being equal to
Answer
  • energy times time
  • energy consumed
  • energy wasted
  • energy times distance
  • energy per unit time

Question 3

Question
The energy source most used in the United States is
Answer
  • coal
  • water
  • natural gas
  • oil
  • biomass (wood)

Question 4

Question
The two factors that influence energy consumption are:
Answer
  • supply and demand
  • resource and price
  • cost and production
  • lifestyle and efficiency

Question 5

Question
If you started with a $1,600 investment and you had $12,800 after 6 years, what would be the annual interest rate you received?
Answer
  • 14%
  • 15%
  • 35%
  • 19%

Question 6

Question
What is the amount of power in kilowatts consumed per capita in the United States?
Answer
  • 2 kW
  • 3 kW
  • 12 kW
  • 5 kW

Question 7

Question
Running a clothes dryer for 90 minutes (1.5 hours) at 1600 Watts will cost about ____ cents if the cost of electricity is 10 cents per kWh:
Answer
  • 4 cents
  • 10 cents
  • 50 cents
  • 24 cents

Question 8

Question
The growth rate of GDP of a certain country is 3.5% per year. This means that the GDP is doubling every ____
Answer
  • 2 years
  • 10 years
  • 5 years
  • 20 years

Question 9

Question
A simple machine, such as a set of pulleys and ropes, known as block and tackle, are devices or tools that multiply applied-force, and changes its direction, at the expense of:
Answer
  • speed
  • velocity
  • distance
  • acceleration

Question 10

Question
The following statement is describing which of the three Newton's Laws of Motion? When no-net force is acting is acting on an object, if it is at rest it remains at rest, or if it is in motion, it can only move at a constant velocity.
Answer
  • First law
  • Second law
  • Third law
  • Law of gravity

Question 11

Question
According to Newton's second law of motion, when a net-force acts on an object, the object must be ____
Answer
  • accelerating
  • going at a constant speed
  • moving at constant velocity
  • at rest

Question 12

Question
According to Newtons third law, if the push that the car tires give to the road-surface is the action force, the the reaction force is
Answer
  • the weight of the car
  • the force of the car upon the tires
  • the friction force of the road-surface on the tires
  • the acceleration of the car

Question 13

Question
If a 60 kg person is observed to accelerate at the rate of 4 m/s(^2), the net force responsible for this is
Answer
  • 240 N
  • 100 N
  • 120 N
  • 140 N

Question 14

Question
A car having an initial speed of 9 m/s starts to accelerate at the rate of 4 m/s(^2), the final speed after 5.5 seconds is
Answer
  • 25 m/s
  • 15 m/s
  • 19 m/s
  • 31 m/s

Question 15

Question
A car is moving at 22 m/s (50 mph), when driver sees the traffic light turning red and immediately applies the brakes, decelerating at 6 m/s(^2). What is the car's stopping distance, neglecting the driver's reaction times?
Answer
  • 30.4 m
  • 10.2 m
  • 20.3 m
  • 40.3 m

Question 16

Question
If a stone is dropped from a bridge that is 133 m above the water, how long will it take until the stone hits the water?
Answer
  • 1.7 s
  • 5.2 s
  • 3.1 s
  • 6.2 s

Question 17

Question
A ball is projected straight downward with an initial speed of 20 m/s. After 3 seconds, about how fast is it going?
Answer
  • 30 m/s
  • 45.4 m/s
  • 49.4 m/s
  • 60.5 m/s

Question 18

Question
A ball is projected straight up at an initial speed of 24.5 m/s. After 2.5 seconds, what is it's speed?
Answer
  • 9.8 m/s
  • 14.7 m/s
  • 4.9 m/s
  • 0 m/s

Question 19

Question
How much work is required to increase the velocity of a 4 kg car from rest to 5 m/s?
Answer
  • 100 J
  • 200 J
  • 20 J
  • 50 J

Question 20

Question
The gravitational potential energy of an object, near the Earth's surface, and the work done to lift the object to the height "h" is given by
Answer
  • weight times height
  • mass times height
  • mass times speed
  • mass times acceleration

Question 21

Question
From work-KE theorem, what is the speed of a car of mass 2500 kg, after it is pushed by a force of 500 N over a horizontal distance of 10 m?
Answer
  • 1 m/s
  • 4 m/s
  • 2 m/s
  • 3 m/s

Question 22

Question
When a car is braked to a stop, it's kinetic energy is transformed into
Answer
  • stopping energy
  • energy of motion
  • potential energy
  • heat energy

Question 23

Question
Our nose cracker moved back and forth as shown. The kinetic energy will be greatest at what point? (A -> B -> C)
Answer
  • A
  • B
  • A and C
  • halfway between A and B

Question 24

Question
The efficiency of a lightbulb is the ratio of the
Answer
  • energy input to the energy out of the bulb
  • light output of the bulb to the electrical energy input
  • heat energy out to the electrical energy in
  • voltage output of the bulb to the power input

Question 25

Question
If the energy conversion efficiencies in a 3 step process are 36% for the first step, 44% for the second, and 26% for the third, the overall efficiency is about:
Answer
  • 4%
  • 9%
  • 0.4%
  • 2%

Question 26

Question
For a fossil fueled electrical generating plant, 10,000 Btus of chemical energy input into the plant will result in about how many Btus of waste heat dumped into the environment if the efficiency of power plant is 35%?
Answer
  • 8,800 Btus
  • 10,000 Btus
  • 4,080 Btus
  • 6,500 Btus

Question 27

Question
The first law of thermodynamics states that: heat added to the system, plus work done on the system, equals change in the total energy of the system. This statement is based on-
Answer
  • how heat can be conducted
  • how temperature is increased
  • the principle of conservation of energy
  • the state of the system

Question 28

Question
The second law of thermodynamics states that heat energy flows in the direction of
Answer
  • up, since heat rises
  • higher temperature
  • lower temperature
  • lower entropy

Question 29

Question
The total R-value of a wall made of different layers of materials is obtained by
Answer
  • multiplying the R values of each layer
  • the sum of R values for each layer
  • sum of areas of each layer
  • sum of thicknesses of each layer

Question 30

Question
When ice crystals form in the clouds,
Answer
  • phase change from solid to liquid occurs
  • the thermal mass of the atmosphere increases
  • heat energy is released
  • the atmosphere becomes colder

Question 31

Question
The R-value of material is not related to its
Answer
  • composition
  • area
  • thickness
  • resistance to heat flow

Question 32

Question
An object with a very high specific heat will
Answer
  • decrease in temperature very fast if removed from the source
  • lose its heat very fast
  • always be water
  • take considerably more heat to raise its temperature

Question 33

Question
The efficiency of an electric motor is the ratio of the
Answer
  • energy into the motor to the energy out of it
  • heat released to rotational energy
  • heat plus electricity produced to the electrical input
  • shaft work output to the electrical energy input

Question 34

Question
For a furnace to provide 80,000 Btu/h of thermal energy to a living space, what should the rate of heat supplied by the fuel be if the furnace efficiency is 65%?
Answer
  • 103,000 Btu
  • 15,300 Btu
  • 123,000 Btu
  • 223,000 Btu

Question 35

Question
A heat engine ____
Answer
  • converts work into heat energy
  • can be 100% efficient in the absence of friction
  • can have no cold sink
  • needs a hot source and a cold sink to be able to work

Question 36

Question
The heat transfer by conduction through an area 10ft x 7ft section of the wall, with R-value of 35 (ft^2-F-h/Btu), with temperature difference between the sides change in temperature equaling 10 degrees farenheit, will be
Answer
  • 10 Btu/h
  • 35 Btu/h
  • 15 Btu/h
  • 20 Btu/h

Question 37

Question
Since the rate of heat transfer by conduction is proportion to the change in temperature, what percent savings in your cooling bill would you expect if you turned the thermostat up from 70 degrees to 74 degrees, and the outside temperature is 95 degrees?
Answer
  • 26%
  • 46%
  • 6%
  • 16%

Question 38

Question
Thermal radiations are electromagnetic waves and like all EM waves are of the type
Answer
  • transverse waves
  • longitudinal waves
  • surface waves
  • torsional waves

Question 39

Question
Normally the phase changes from vapor to liquid to solid takes place in that order when the heat is
Answer
  • kept constant
  • pressure is reduced
  • added
  • removed

Question 40

Question
85 degrees Fahrenheit is equal to ____ temperature in Kelvin scale
Answer
  • 286 K
  • 308 K
  • 316 K
  • 302 K

Question 41

Question
The Carnot efficiency (maximum possible efficiency) of a heat engine operating between 20 degrees C and 2000 degrees C will be about ____. (Note: the temperature must be in Kelvins -> C + 273)
Answer
  • 35%
  • 100%
  • 72%
  • 87%

Question 42

Question
A heat pump will have an efficiency of about ____
Answer
  • 35%
  • 100%
  • 200%
  • 50%

Question 43

Question
What are the percentages of Infra-Red (IR), Ultra Violet (UV), and Visible Light in the solar radiation at the top of the Earth's atmosphere?
Answer
  • 17% IR, 37% UV, 46% visible
  • 37% IR, 5% UV, 58% visible
  • 51% IR, 12% UV, 37% visible
  • 47% IR, 7% UV, 46% visible

Question 44

Question
The amount of infrared radiation emitted, or absorbed, by an object, apart from the temperature difference with the surroundings, and the surface area, depends also on
Answer
  • shape
  • color, surface texture
  • its type of material
  • density

Question 45

Question
What is the wavelength of the electromagnetic waves emitted by a Satellite-TV, that has typically a frequency of 12 GHz? (GHz= 10^9 Hz)
Answer
  • 0.015 m
  • 0.025 m
  • 0.035 m
  • 0.013 m

Question 46

Question
Specific heat of a substance is defined as the
Answer
  • heat required to increase its temper by one-degree Fahrenheit
  • heat required to increase its temperature by one-degree Celsius
  • heat required to increase its heat by one joule
  • heat required to increase the temperature one one unite mass by one degree

Question 47

Question
How much heat energy is required to increase the temperature of 3 kg of water from room temperature of 20 degrees C to the boiling point 100 degrees C? (Specific heat of water in SI units is C= 4186 J/kg*C)
Answer
  • 20.4 kJ
  • 50.6 kJ
  • 100.5 kJ
  • 789.7 kJ

Question 48

Question
What produces the cooling in a refrigerator?
Answer
  • evaporation of Freon outside
  • compression on Freon inside
  • condensation of Freon
  • evaporation of Freon inside

Question 49

Question
The geothermal heat, that is, the heat from the interior of the earth, can be used to warm or cool a house
Answer
  • in a certain area
  • near hot water springs
  • eight feet below the ground everywhere
  • more than 100 feet underground

Question 50

Question
A wall of a typical house is made of six layers with R-values given in (ft^2- F - h/Btu); from interior dead air later (R1= 0.68), 0.5 in sheetrock (R2= 0.45), 5.5 in fiberglass insulation (R3= 19), 0.5 in plywood (R4= 0.63), exterior dead air layer (R5 = 0.68). If temperature difference between outside and inside is 22 degrees F, and the total area of the wall is 360 ft^2 the rate of heat transfer by conduction is ____.
Answer
  • 567.4 Btu/h
  • 156.3 Btu/h
  • 369.4 Btu/h
  • 423.6 Btu/h

Question 51

Question
The Carnot efficiency of a heat engine operating between 21 degrees C and 1200 degrees C will be about
Answer
  • 52%
  • 78%
  • 80%
  • 90%

Question 52

Question
Amount of heat and temperature of an object are different because amount of heat depends on the
Answer
  • temperature difference
  • energy of its molecules
  • size of its molecules
  • amount of substance

Question 53

Question
The first law of thermodynamics is related to the
Answer
  • conservation of energy
  • heat and temperature
  • entropy and temperature
  • heat and work

Question 54

Question
To keep an iced drink cold for the longest time, what color cup would you use?
Answer
  • red
  • blue
  • white
  • black

Question 55

Question
Suppose it takes 48,000 Btu to heat up the water in a tank. If the heating element has an output of 2,800 W, then how long will it take to heat up the water, assuming no extra heat losses?
Answer
  • 2 h
  • 5 h
  • 30 mins
  • 3 h

Question 56

Question
The existence of the four seasons, in the mid-latitude locations, is due to the
Answer
  • moon-earth interaction
  • variation of the sun-earth distance
  • tilt of rotation axis of the earth by 23.5 degrees
  • variation of the moon-earth distance

Question 57

Question
Heat transfers by all three ways; conduction, convection, and radiation; are directly proportional to the....
Answer
  • surface temperature
  • surface roughness
  • surface color
  • surface area

Question 58

Question
The optimal angle of tilt, from the horizontal, for a south facing flat-plate solar collector, or photovoltaic cells panel, in a location with the latitude of 50.5 degrees N, for the purpose of solar panels installation is
Answer
  • 50.5 degrees
  • 60.5 degrees
  • 20.5 degrees
  • 30.5 degrees

Question 59

Question
What is the main advantage of using thermal mass, in the form of thick concrete floor, or Trombe wall, in a direct-gain passive solar system?
Answer
  • to increase temperature fluctuations during the night
  • to provide foundation support for the collector superstructure
  • to increase the insolation on south-facing windows
  • to reduce temperature fluctuations during the day

Question 60

Question
During what season will more insolation be delivered to a vertical south-facing window on a clear day?
Answer
  • fall
  • winter
  • spring
  • summer

Question 61

Question
The insolation in a certain location is 900 W/m^2 and 85% of this is direct component on the collector. If a useful rate of energy needed for cooking is 150 W, then what area of the solar collector oven in the form of parabolic mirror is needed to intercept this amount of radiation, take the efficiency to 20%?
Answer
  • 0.98 m^2
  • 1.2 m^2
  • 1.6 m^2
  • 0.87 m^2

Question 62

Question
Determine the collector area needed to heat 554 lbs of water (80 gallons), in one day, from 50 degrees F to 130 degrees F, if the insolation is 1700 Btu/d/ft^2 and the FPC efficiency is 48%.
Answer
  • 54 ft^2
  • 62 ft^2
  • 73 ft^2
  • 33 ft^2

Question 63

Question
The main difference between transverse and longitudinal waves is that transverse waves
Answer
  • travel faster than longitudinal waves
  • are not shear waves
  • can not be polarized
  • can be polarized

Question 64

Question
A typical microwave generates the electromagnetic waves of frequency 2.45 GHz (1 Giga= 10^9). The wavelength of the radio wave corresponding to the frequency is
Answer
  • 9.26 cm
  • 8.48 cm
  • 11.45 cm
  • 12.24 cm

Question 65

Question
In prospection for ore by gravimetric method, (to measure the variation of g=9.8 m/s^2 on the earths surface at a fixed height) how do you distinguish between petroleum and ore?
Answer
  • g would be greater over an ore deposit than a petroleum deposit
  • density of ore is less than petroleum
  • g does not change over the surface of the earth
  • g would be greater over a petroleum deposit than an ore deposit

Question 66

Question
When seismic waves (or light waves) travel from one medium into another medium with different wave-speed, what is the difference between reflection and refraction, at the interface between the two media?
Answer
  • Refracted wave bends and goes through the second medium
  • reflection and refraction are the same effect
  • reflection can only occur on a smooth interface
  • refraction will not bend the direction of the waves

Question 67

Question
What is the main difference between electromagnetic waves and sound waves?
Answer
  • electromagnetic waves can travel in a vacuum
  • sound waves travel faster
  • sound waves can be polarized
  • sound waves can travel in a vacuum

Question 68

Question
The magnitude of gravitational attraction between a 135 kg-person and a 290,000 kg-door of a bunker, with 0.2 m distance between their centers of mass is ____. (G= 6.674 x 10^-11 n*m2/kg2)
Answer
  • 6.53 x 10^-2 N
  • 7.64 x 10^-3
  • 8.75 x 10^-3
  • 5.42 x 10^-2

Question 69

Question
In a fractionating tower of an oil-refinery, where crude oil is heated from the bottom to separate different hydrocarbon constituents, what is the least volatile constituent of crude oil? That is, the component with the highest boiling point?
Answer
  • industrial fuel oil
  • kerosene
  • gasoline
  • asphalt

Question 70

Question
The longevity of a fossil-fuel reserve is determined by the ratio of
Answer
  • proven reserves/ daily production production rate
  • proven reserves / yearly production rate
  • indicated reserves / yearly production rate
  • inferred reserves yearly production rate

Question 71

Question
Pressure on a surface inside a fluid is due to the
Answer
  • force of gravity
  • rotational energy of fluid molecules
  • surface tension
  • continuous knocking of fluid molecules on the surface

Question 72

Question
Static pressure at a depth h below the surface of a fluid is given by
Answer
  • mass x g x h
  • density x g x h
  • force x time x h
  • h x g x volume

Question 73

Question
A swimming pool has a depth of 2.5 m. What is the gauge pressure at the bottom of this pool, in psi? (Density of water is pw= 1000 kg/m3)
Answer
  • 3.553 psi
  • 4.652 psi
  • 7.324 psi
  • 1.334 psi

Question 74

Question
The normal blood pressure is expressed as 80 to 120 mm-of-mercury, which are gauge pressure values. When these values are converted into psi they become ____
Answer
  • 1.432, 2.133 psi
  • 1.547, 2.320 psi
  • 1.652, 2.358 psi
  • 1.321, 2.142 psi

Question 75

Question
A balloon in the air is buoyed up by a force equal to the
Answer
  • weight of the air it displaces
  • weight of the balloon and its contents
  • mass of air displace
  • density of the surrounding air

Question 76

Question
What is the buoyant force on a 3 ton ship that is floating in the sea?
Answer
  • 2.5 tons
  • 3.0 tons
  • 3.5 tons
  • 1.5 tons

Question 77

Question
Why do you expect photochemical smog to be a greater problem in a city like Los Angeles than in a heavily industrialized city like Pittsburgh?
Answer
  • LA has more automobile traffic
  • LA gets more days with temperature inversion
  • LA is less windy
  • Pittsburg has more desulfurization plants

Question 78

Question
The acidity of rain, or other solutions, is measured by the pH number scale that varies from 0 to 14. What does a pH number represent?
Answer
  • 10 to the positive power of the hydrogen ion concentration
  • the larger the pH number the stronger the acidity
  • the smaller the pH number the less acidic the solution is
  • 10 to the negative power of the hydrogen ion concentration in the solution

Question 79

Question
The pressure exerted on your finger if you hold up a 15 lb box of apples, if the contact surface of your finger is 0.25 in x 0.25 in, would be ____
Answer
  • 200 psi
  • 220 psi
  • 240 psi
  • 160 psi

Question 80

Question
Suppose it takes 38,500 Btu to heat up water in a tank. If the heating element has an output power of 2,500 W, then how long would it take to heat up the water, assuming no extra heat losses? (1 Btu= 1055 Joules, 1 Watt = 1 Joule per second, 1 hour = 3600 s)
Answer
  • 55 mins
  • 2.5 hours
  • 3.5 hours
  • 4.5 hours

Question 81

Question
During which season will more insolation be delivered to a vertical south facing window on a clear day?
Answer
  • Winter
  • Fall
  • Spring
  • Summer

Question 82

Question
The optimum angle of tilt from the horizontal, for a flat plate solar collector, or panels of photovoltaic cells, both facing South, in a location with a latitude of 50.5 degrees North, for the purpose of solar panel installations is
Answer
  • 30.5 degrees
  • 40.5 degrees
  • 50.5 degrees
  • 60.5 degrees

Question 83

Question
The measure of the angle of position of the sun from the South direction is called the
Answer
  • altitude
  • azimuth
  • declination
  • inclination

Question 84

Question
If the insolation (I) upon a flat plate collector is 890 (Btu/ft2*day), how large must the area A of the collector be to provide (Q/t= 12,400 Btu/hr of thermal energy for one day (24 hours)? Take the collector efficiency to be 57.5% (Note: Btu/h is related to I A and E by Q/t = I*A*E)
Answer
  • 18 ft2
  • 164 ft2
  • 376 ft2
  • 637 ft2

Question 85

Question
The acidity of rain, or a solution, is measured by the pH number, that varies from 0 to 14, what does a pH number represent?
Answer
  • 10 to the positive power represent the hydrogen ion concentration per mole
  • the larger the pH the stronger the acidity of the solution
  • 10 to the negative power of the hydrogen ion concentration per mole in the solution
  • the smaller the pH the less acidic the solution

Question 86

Question
Pressure on a surface is defined as
Answer
  • mass x speed
  • mass x velocity
  • density x volume
  • force per unit area

Question 87

Question
Pressure on a surface inside a fluid is caused by
Answer
  • weight of fluid molecules
  • force of gravity
  • potential energy of fluid molecules
  • repeated knocking of the fluid molecules on the surface

Question 88

Question
Static pressure at a depth h in a fluid is given by
Answer
  • h x g x volume
  • mass x g x h
  • force x time x h
  • density x g x h

Question 89

Question
Atmospheric pressure, at sea level, is 14.7 psi, the gauge pressure of an automobile tire is 38 psi, the absolute pressure of this tire in Pascal is..... (Note: 1 psi = 6895 Pa)
Answer
  • 131,100 Pa
  • 248,200 Pa
  • 353,300 Pa
  • 363,400 Pa

Question 90

Question
A balloon in the air is buoyed up by a force equal to the ___
Answer
  • density of the surrounding air
  • atmospheric pressure
  • weight of the balloon and its contents
  • weight of the air it displaces

Question 91

Question
Which of the following air pollutants is emitted in about equal amounts by stationary and mobile sources?
Answer
  • particulates
  • carbon monoxide
  • nitrogen oxides
  • sulfur dioxides

Question 92

Question
Ozone layer in the stratosphere
Answer
  • dissipates within days
  • combines with NO or NO2 to produce smog
  • absorbs infrared light from the sun
  • provides protection from incoming UV solar radiation

Question 93

Question
How much has the global temperature on earth changed over the past 100 years?
Answer
  • 0.5 degrees C
  • 1.0 degrees C
  • 1.5 degrees C
  • 2.0 degrees C

Question 94

Question
One of the fundamentals of electrostatic is that the force between two unlike charges is
Answer
  • repulsive
  • neutralized
  • attractive
  • zero

Question 95

Question
Electricity is transmitted from plower plants at ____ to reduce by Joule heating in the transmission lines, which is about 10%.
Answer
  • high currents
  • low resistance
  • high resistance
  • high voltage

Question 96

Question
What quantity is the same for three resistors in a series circuit?
Answer
  • power
  • resistance
  • current
  • voltage

Question 97

Question
What quantity is the same for three resistors in a parallel circuit?
Answer
  • power
  • resistance
  • current
  • voltage

Question 98

Question
A circuit consists of one lightbulb of resistance of 144 ohms and another lightbulb of 240 ohms that are wired in series to a 120 V wall socket outlet. What is the current through this circuit?
Answer
  • 0.10 A
  • 0.20 A
  • 0.30 A
  • 0.40 A

Question 99

Question
Two resistors of 144 ohms and 240 ohms are wired in parallel to 120 V wall outlet socket outlet, the current through the 240 ohm resistor will be
Answer
  • 0.3 A
  • 0.4 A
  • 0.5 A
  • 0.6 A

Question 100

Question
The electrostatic force of attraction between two charges of q1= -35 x 10^-6 C and q2 = +69 x 10^-6 C, separated by a distance of 3 m is ___
Answer
  • 0.4 N
  • 1.21 N
  • 2.41 N
  • 3.53 N

Question 101

Question
A high temperature superconductor compounds such as YBCO ____
Answer
  • provides large magnetic fields at room temperature
  • has no resistance at room temperature
  • has no electrical resistance below its critical temperature
  • generates constant voltage at low temperatures

Question 102

Question
A lightbulb draws a current of 2.5 amps, when connected to a wall outlet of 120 V. What is the resistance of the bulb?
Answer
  • 50 ohms
  • 100 ohms
  • 200 ohms
  • 300 ohms

Question 103

Question
The resistance of four light bulbs are given below. Which one has the highest wattage?
Answer
  • 144 ohms
  • 192 ohms
  • 240 ohms
  • 320 ohms

Question 104

Question
How much current is drawn by 3240 W electrical appliance operating at 240 V?
Answer
  • 11.3 A
  • 12.4 A
  • 13.5 A
  • 14.5 A

Question 105

Question
What is the cost of running your water heater of power rating 2800 W for 2.5 hours per day, for one year or 365 days, if the electricity costs 12 cents per kWh?
Answer
  • $95
  • $105
  • $206
  • $307

Question 106

Question
The magnetic field of a bar magnet is similar to that produced by
Answer
  • a horse shoe magnet
  • a straight current carrying wire
  • two coils separated by long distance
  • a current carrying solenoid

Question 107

Question
Alternating current has an advantage over direct current because
Answer
  • batteries can be displaced in most circuits
  • electrical generators can be made
  • produces no heat loss
  • one can step up, or down, the amount of voltage used

Question 108

Question
A transformer (adaptor) can only operate if
Answer
  • the power in equals the power out
  • an alternating current is used
  • the potential difference is large enough
  • we step down the current

Question 109

Question
If the current through a 33 ohm resister and a 57 ohm resistor in series is 5 A, then the total voltage drop across both of these resistors will be
Answer
  • 110 V
  • 120 V
  • 340 V
  • 450 V

Question 110

Question
What transformer turns-ratio of secondary to primary is required to lower the voltage from 120 V wall socket outlet to 8 V for charging a cell phone?
Answer
  • 15
  • 0.044
  • 0.075
  • 0.067

Question 111

Question
A bird sitting on a bare high voltage wire is not electrocuted because ____
Answer
  • of the high resistance of its body
  • its body is at a low electrical potential compared to the wire
  • the high voltage across its feet produced a small current
  • there is no electrical potential difference across its body because the other wire is out of reach

Question 112

Question
For a photovoltaic cell of 0.5 V and of area 1 cm2, the maximum output power is 135 mW (mW= 10^-3 W). What is the current provided by this cell?
Answer
  • 0.01 A
  • 0.02 A
  • 0.23 A
  • 0.27 A

Question 113

Question
The site location for a wind turbine is especially important. If the power output goes as the cube of the wind velocity, then which of the following average velocities will give approximately 8 times as much output as 10 mph winds?
Answer
  • 5 mph
  • 10 mph
  • 15 mph
  • 20 mph

Question 114

Question
If the average wind speed for 24 hours is 16 mph at one site but 13 mph at another site for 12 hours and then 23 mph for 12 hours at another site, how much output can be expected from the first turbine compared to the turbine at the second site?
Answer
  • 35%
  • 46%
  • 57%
  • 68%

Question 115

Question
A 1000 MW power plant is shut down for one day (24 hours). What is the loss of income from this plant if the selling price were 10 cents/kWh (1 MW=10^6 kW).
Answer
  • $180,000
  • $700,000
  • $2,400,000
  • $3,500,000

Question 116

Question
For the following circuit, with all the bulbs identical, what is true for the brightness of the lights? l -----------l (A) l l_____ l (B) l l (C) l _______ l ____ l
Answer
  • A = B = C
  • A = 4B = 4C
  • A = .5B = .5C
  • A = B, C = 0

Question 117

Question
The existence of atom was proposed by Democritus (420 BCE) and at the beginning of the 19th century, John Dolton proved that every element has an atom, by the ____
Answer
  • law of electrostatics
  • ideal gas law
  • law of definite proportion
  • law of conservation of energy

Question 118

Question
The discovery of atomic nucleus was made by firing fast moving ____ at a thin gold foil
Answer
  • alpha particles
  • gamma rays
  • electrons
  • neutrons

Question 119

Question
The isotopes of an element all have the same number of
Answer
  • protons
  • electrons
  • positron neutrons
  • nucleons

Question 120

Question
For the same energy, the most penetrating type of radiations are
Answer
  • B-particles
  • X-rays
  • a-particles
  • y-rays

Question 121

Question
The half-life of a radioactive nuclide is the time taken for _____
Answer
  • half of its neutrons to decay
  • half of its electrons to decay
  • half of its mass to decay
  • half of its nuclei to decay

Question 122

Question
At 9 am on Monday, a radioactive sample contained 80 million nuclei. At 9 am on Saturday, 2.5 million of these nuclei are left over and has not decayed. The half life of the sample is
Answer
  • 1.5 days
  • 1 day
  • 5 days
  • 4 days

Question 123

Question
The radioactive isotope Cobalt-60 decays into Nickel-60 by beta emission, with a half life of 5.3 years. If we start with 100 gram of Co-60, after how many years will we have only 390 milligrams of it left?
Answer
  • 20
  • 42
  • 89
  • 6

Question 124

Question
The activity of Carbon-14 in the living organism today is 15.3 disintegrations per minute, per gram. Half-life of Carbon-14 is 5730 years. If the activity of an archaeological sample, due to the carbon-14 is 3.825 disintegrations per min, per gram, how old is the sample?
Answer
  • 2865
  • 5730
  • 11460
  • 22920

Question 125

Question
The binding energy of a Helium nucleus is 4.5 x 10^-12 Joules (28.4 MeV). What is the total binding energy of 4-grams (one mol.) of Helium that has avogadro's number NA= 6.02 x 10^23 of nuclei, when this mass is converted into radiant energy in the interior of the Sun?
Answer
  • 1.7 x 10^11 J
  • 2.7 x 10^12 J
  • 1.2 x 10^10 J
  • 3.4 x 10^13 J

Question 126

Question
The pair production and annihilation refer to the simultaneous production of a particle and its anti-particle by two energetic gamma-ray photons, near a nucleus, and the destruction of a particle and an anti-particle, as a result of collision between them, these particles and anti-particles can be _____
Answer
  • electron and positron
  • proton and electron
  • proton and neutron
  • two neutrons

Question 127

Question
In the following fission reaction, the atomic number Z and mass number of nucleus A of the unknown element Y are: (0/1)n + (92/235)U --> (53/135)I + (Z/A)Y + (0/2)n
Answer
  • 38, 102
  • 39, 99
  • 39, 100
  • 37, 100

Question 128

Question
If a light-weight stable nucleus has 12 neutrons, the atomic mass is expected to be _____. (1 atomic mass unit = 1.66 x 10^-27 kg).
Answer
  • 18 amu
  • 24 amu
  • 36 amu
  • 6 amu
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