ALL Physics HW questions

A fixed mass of gas initially occupies a 2L volume at atmospheric pressure. It undergoes an isobaric change to a volume of 5L, followed by isochoric change to a pressure of 2 atmospheres. See path (iii) in Figure. If the system is brought back to its initial state along the reverse of path (i), what is the net work done on the gas? a.304 J b.-152 J c.-456 J d.152 J

A

A fixed mass of gas initially occupies a 2L volume at atmospheric pressure. It undergoes an isobaric change to a volume of 5L, followed by isochoric change to a pressure of 2 atmospheres. See path (iii) in Figure. If the system is brought back to its initial state along the reverse of path (ii), what is the net work done on the gas? a.152 J b.-152 J c.456 J d.-456 J

A

An 80-kg man climbs stairs to reach the top floor of a building, a total change of height of 30 m. As a result, he uses up 26 Cal (1 Cal =1 kcal; 1 cal = 4.184 J) of stored food energy. How much heat must his body dissipate? a.85 kJ b.55 kJ c.21 kJ d.12 kJ

A

An air bubble has a volume of 19 cm3 when it is released by a submarine several meters below the surface of a lake. If the pressure at that level of the water is 10.3 times the pressure at the surface (atmospheric pressure), what is the volume of the bubble in cm3 when it reaches the surface? . (Assume the temperature and the number of air molecules in the bubble remain constant during its ascent.) a. 196 b. 799 c. 305 d. 111.4

A

An ideal gas is confined to a container with adjustable volume. The pressure and mole number are constant. By what factor will volume change if absolute temperature triples? a.3.0 b.9.0 c.1/9 d.1/3

A

An iron bullet of mass 100 g and travelling at 500 m/s hits a fixed iron plate of mass 400 g. Assuming the bullet is brought to rest on hitting the plate, what temperature rise occurs in the iron, assuming the temperature distribution is uniform? Specific Heat Capacity of iron is 448 J/Kg·K a.56°C b.6°C c.70°C d.7°C

A

During inhalation, the pressure in the lungs is smaller than atmospheric pressure. A. True B. False

A

Gas in a container with a volume of 1.50 L at a temperature of 0°C exerts a pressure of 2.00 atmospheres. How many moles of gas are in the container? a.0.13 b.0 c.0.26 d.1.30 e.130

A

How may electric field lines be represented graphically? a.The direction of the field is tangent to the line; magnitude is shown by local density of lines. b.The direction of the field is tangent to the line; magnitude is shown by thickness of lines. c.The direction of the field is perpendicular to the line; magnitude is shown by thickness of lines. d.The direction of the field is perpendicular to the line; magnitude is shown by local density of lines.

A

If the volume of an ideal gas is doubled while its temperature is quadrupled, does the pressure? a.increase by a factor of 2 b.increase by a factor of 4 c.decrease by a factor of 4 d.remain the same e.decrease by a factor of 2

A

In Figure, a piston of cross-section 1 m2 seals a cylinder of gas of length 0.5 m, at atmospheric pressure (so that there is no net force on the piston). The gas is at the ambient temperature of 20°C, then the gas is heated to 100°C. What extra force must the piston exert to contain the gas in the cylindrical space of reduced length 0.4 m? a.6.0´10^4 N b.1.2´10^5 N c.5.3´10^5 N d.3.0´10^4 N

A

In Joule's experiment, if a 10.0 kg mass falls a distance of 1.0 m, and the paddle is immersed in a 0.5L beaker of mercury, what is the rise in temperature of the mercury, given that its mass density is 13.5 g/cm3 and its specific heat capacity is 138 J/(kg°C)? a.0.105 °C b.0.001 °C c.1.05 °C d.0.01 °C

A

In the First Law of Thermodynamics, W is the work done on the system, that is, W is positive if work is done on the system. A. True B. False

A

One way to heat a gas is to compress it. A gas at 1.00 atm at 25.0°C is compressed to one tenth of its original volume, and it reaches 40.0 atm pressure. What is its new temperature? a.919°C b.1 500 K c.1 500°C d.1 192°C

A

The gas in a constant-volume gas thermometer registers a pressure of 110 kPa at 140 ºC. Assuming ideal behaviour, what is the temperature of this gas in celcius when the pressure is 210 kPa? a.516 ºC b.789 ºC c.267 ºC d.-57 ºC e.73 ºC

A

What is a hydration shell? a.a collection of water molecules that surround an ion in solution b.a shell of hydrogen atoms that surrounds an ion in solution c.a collection of water molecules that surround a negative ion in solution d.a collection of water molecules that surround a positive ion in solution

A

What is the resultant magnitude and direction of the force on a 5 mC charge situated on the y-axis, 4.0 cm from the point of origin, due to a pair of 3 mC charges located on the x-axis at opposite sides of the point of origin, each at distance of 3.0 cm from the point of origin? a.86.4 N in the (+y) direction b.108.0 N in the (-y) direction c.108.0 N in the (+y) direction d.86.4 N in the (-y) direction

A

When the distance to a polar molecule is doubled, the electric field due to the dipole decreases by what factor? a.8 b.64 c.16 d.4

A

A 2.00-L container holds half a mole of an ideal gas at a pressure of 12.5 atm. What is the gas temperature? (R = 0.082 1 L×atm/mol×K) a.1 190 K b.609 K c.965 K d.1 980 K

B

A charge of +2 C is at the origin. When charge Q is placed at 2 m along the positive x axis, the electric field at 2 m along the negative x axis becomes zero. What is the value of Q? a.-6 C b.-8 C c.-3 C d.-7 C

B

A gas expands from A to B as shown in the graph. Calculate the work (in joules) done by the gas. (1 atm= 1.013 ´ 105 N/m2.) a.24 b.1.2 ´ 10^6 c.12 d.3.6 ´ 10^6 e.2.4 ´ 10^6

B

Compressing gas in a closed system does negative work on the gas. A. True B. False

B

Four charges of +10.0 µC are placed at the four corners of a square that is 50.0 cm on each side. What is the magnitude of the electric field at the centre of the square? a.2.9 N/C b.0 N/C c.2.1 N/C d.0.7 N/C

B

How does the pressure in the lungs at rest compare with atmospheric pressure? a.always lower b.always the same c.always higher d.varies during the breathing cycle

B

In the first law of thermodynamics DU = Q + W, Q is the heat lost by the system, that is, Q is positive if the system loses heat. A. True B. False

B

Two parallel plates are immersed in salt water, and a battery is connected to the plates. What happens at the surface of the positively-charged plate? a.Both Cl and Na ions migrate to the plate, with their hydration shells removed. b.Cl ions migrate to the plate. c.The hydration shells around the Na and Cl ions shield them from the electric field, so nothing happens. d.Na ions migrate to the plate.

B

Two protons in the nucleus of a helium atom are 2´10-15m apart. What is the minimum strength of the nuclear strong force of attraction that is required to hold the nucleus together against Coulomb repulsion? a.29 N b.58 N c.6 N d.1 N

B

he electric field of a point charge has an inverse ________ behavior. a.r b.r^2 c.r^1/2 d.r^3

B

2.0 moles of an ideal monatomic gas are initially at a temperature of 300 K. If the gas gains 2800 J of heat and performs 400 J of work, what is its final temperature?Use DU = 3/2 n R DT for ideal monoatomic gas a.204°K b.251°K c.396°K d.515°K

C

A gas expands as shown in the graph. If the heat taken in during this process is 1.02 ´ 106 J and 1 atm = 1.013 ´ 105 N/m2, the change in internal energy of the gas (in J) is a.-2.4 ´ 10^6 b.-1.4 ´ 10^6 c.1.4 ´ 10^6 d.-1.0 ´ 10^6 e.1.0 ´ 10^6

C

A substance is heated from 23°C to 47°C. What would the same incremental change be when registered in kelvins? a. 297 b. 90 c. 24 d. 56

C

An athlete doing push-ups performs 700 kJ of work and loses 450 kJ of heat. What is the change in the internal energy of the athlete? a.1150 kJ b.250 kJ c.-1150 kJ d.-250 kJ

C

An electron with a charge value of 1.6 ´ 10-19 C is moving in the presence of an electric field of 400 N/C. What force does the electron experience? a.4.9 ´ 10-17 N b.2.3 ´ 10-22 N c.6.4 ´ 10-17 N d.1.9 ´ 10-21 N

C

Consider two copper balls, each of one molar mass, and 10.0 m apart. Suppose 0.01% of the atoms in one ball acquire an excess positive charge of +e each, and 0.01% of the atoms in the other ball acquire an excess negative charge of -e each. What is the electric force between them? a.8.0´105N b.0.96 N c.8.3´109 N d.9.6´108N

C

How is the molar heat capacity C of a substance of molar mass M related to the specific heat capacity c? a.c = nC, where n = number of moles b.c= MC c.C = Mc d.C = nc, where n = number of moles

C

If we double the charge on two point charges, and double the distance between them, how much does the electric force between them change? a.doubled b.four times larger c.remains the same d.halved

C

In Figure, by which closed path (cyclic process), starting and ending at "initial" and passing through "final," will the most work be done on the gas? a.(iii) followed by reverse of (ii) b.(ii) followed by reverse of (i) c.(iii) followed by reverse of (i) d.(i) followed by reverse of (iii)

C

In the equation DU = Q + W, which of the following statements is false? a.W is positive when work is done on a system b.W is negative when work is done by a system c.Q is positive when heat flows out of the system d.When heat flows into a system and no work is done, the internal energy of the system increases.

C

Pressure in a gas is reduced by 1/4 of its initial value, and the temperature reduced to 90% of its initial value. What is the ratio of final to initial volume of the gas? a.0.23 b.3.70 c.3.60 d.3.80 e.7.60

C

A certain gas in a closed container at 0.001 atmospheres of pressure is irradiated with ionizing radiation, causing on average one electron to be stripped off each atom. The ionizing radiation also heats the gas from 20°C to 3000°C. The resulting ionized gas ("plasma") behaves like an ideal gas. What is the pressure in the plasma? a.3.04´10^5 Pa b.4.92´10^3 Pa c.1.23´10^3 Pa d.2.26´10^3 Pa

D

A gas expands from an initial volume of 0.015 m3 to a final volume of 0.075 m3 while its pressure increases linearly with the volume (so that the process follows a straight-line path in a P-V diagram) from 80 kPa to 275 kPa. How much work is done by the system? a.-5.6 kJ b.-10.6 kJ c.5.6 kJ d.10.6 kJ

D

An ideal gas is confined to a container with adjustable volume. The number of moles and temperature are constant. By what factor will the volume change if pressure triples? a.9.0 b.3.0 c.1/9 d.1/3

D

Electric field is dimensionally equivalent to which of the following? a.N/C^2 b.N×m/C c.N×m^2/C2 d.N/C

D

For isobaric change, which of the following is false? a.Volume is proportional to temperature. b.Pressure is constant. c.Density is inversely proportional to temperature. d.Density is proportional to temperature.

D

In Figure, by which closed path (cyclic process), starting and ending at "initial" and passing through "final," will the most work be done by the gas? a.(iii) followed by reverse of (i) b.(iii) followed by reverse of (ii) c.(ii) followed by reverse of (i) d.(i) followed by reverse of (iii)

D

The surfaces of a lipid bi-layer forming the membrane around a cell with a radius of 2 μm has a residual charge qr = 7.7×10-15 C on outside of the bi-layer, and the same amount of negative charge on the inside. What is the force in pN (×10-12 N) on a singly-charged positive ion (q =1.6 ×10-19 C) located on the outer surface of this membrane? Hint: Use F = q E = q (σ/e) with σ = qr/A = qr/ (4π r2) and εo = 8.85 x 10-12 F·m-1. a. 7.9 b. 3.8 c. 5.4 d. 2.77

D

Two point charges are 4 cm apart. They are moved to a new separation of 2 cm. By what factor does the resulting mutual force between them change? a.1/2 b.2 c.1/4 d.4

D

With volume and molar quantity held constant, by what factor does the absolute temperature change for an ideal gas when the pressure is five times bigger? a.1.0 b.0.2 c.25.0 d.5.0

D

In a thermodynamic process, the internal energy of a system in a container with adiabatic walls (this means Q = 0) decreases by 800 J. Which statement is correct? a.The system gained 800 J by heat transfer from its surroundings. b.The surroundings performed 800 J of work on the system. c.The system lost 800 J by heat transfer to its surroundings. d.The 800 J of work done by the system was equal to the 800 J of heat transferred to the system from its surroundings. e.The system performed 800 J of work on its surroundings.

E

Where does the energy required for inhalation come from? a.energy of air flowing into lungs b.actions of muscles, diaphragm, and thorax c.elastic action of thorax alone d.internal energy of air in lungs

A

A gas expands from an initial volume of 5.0 L to a final volume of 20.0 L at a constant pressure of 350 kPa. How much work is done by the gas? a.8.75 kJ b.5.25 kJ c.-5.25 kJ d.-8.75 kJ

B

A gas expands from an initial volume of 5.0 L to a final volume of 20.0 L at a constant pressure of 350 kPa. How much work is done on the gas (W)? a.8.75 kJ b.-5.25 kJ c.-8.75 kJ d.5.25 kJ

B

Molybdenum melts at a temperature of 1026°C. What is the corresponding temperature on the Kelvin scale? a. 1400 b. 1299 c. 873 d. 1089

B

Normal body temperature for humans is 37°C. What is this temperature in kelvins? a.393 b.310 c.273 d.296

B

The pressure in a constant-volume gas thermometer extrapolates to zero at what temperature? a.0°F b.0 K c.0 Pa d.0°C

B

The sum of all energy forms in a closed system is constant. A. True B. False

B

Two charges, +Q and -Q, are located two meters apart and there is a point along the line that is equidistant from the two charges as indicated. Which vector best represents the direction of the electric field at that point? a.Vector EB b.Vector EA c.Vector EC d.The electric field at that point is zero.

B

Two moles of an ideal gas at 3.0 atm and 10°C are heated up to 150 °C. If the volume is held constant during this heating, what is the final pressure? a.0.14 atm b.4.5 atm c.1.0 atm d.1.8 atm

B

The combination of two separated point charges of opposite sign but equal magnitude is called an electric: a.monopole. b.magnapole. c.dipole. d.quadrapole.

C

The weight of a 1147 kg car is supported equally by the four tires, which are inflated to the same gauge pressure. What gauge pressure in kPa is required so the area of contact of each tire with the road is 55 cm2? a. 820.1 b. 90.4 c. 511 d. 570.8

C

Which of the following does NOT describe the mass and electric charge properties of a particle? a.Charge is quantized into multiples of a basic unit of charge. b.Different masses always attract each other through gravity. c.The gravitational force between charged particles is larger than the electrical force. d.Mass cannot be negative, whereas charges can be either positive or negative.

C

What is the electric field at x = 50 ´ 10-10 m (x >> d) away from a water molecule, along the axis of its dipole? mwater = 6.17 × 10-30 C·m. a.7.1 ´105 N/C b.3.6 ´103 N/C c.3.6 ´104 N/C d.8.9 ´105 N/C e.4.2 ´105 N/C

D

Why does it require latent heat to change water from the liquid to the vapour state? a.Water molecules form a crystal structure, and it takes energy to break up this structure. b.The additional energy is required to raise the mean speed of molecules high enough to escape the liquid. c.Molecules in the liquid phase must reach the boiling point of water before they escape. d.The hydrogen bonds between different water molecules must be broken to allow evaporation.

D