Aluminum rod #1 is 1.0 m long with cross-section area 2.0 cm2. Aluminum rod #2 is 2.0 m long with cross-section area 4.0 cm2. Aluminum rod #3 is 3.0 m long with cross-section area 9.0 cm2. If each rod has the same temperature difference applied across its ends, which rod has the greatest rate of transfer of energy between its ends?

A) #1 B) #2 C) #3 D) #2 = #3, both greater than #1 E) They each have the same rate. A) #1 B) #2 C) #3 D) #2 = #3, both greater than #1 E) They each have the same rate.

Exam 20: The First Law of Thermodynamics

A 100 kg marble slab falls off a skyscraper and falls 200 m to the ground without hitting anyone. Its fall stops within milliseconds, so that there is no loss of thermal energy to its surroundings if its temperature is measured immediately after it stops. By how much has its temperature changed as a result of the fall, if we ignore energy gained or lost as a result of its interaction with the atmosphere? ( .)

(Multiple Choice)

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Question 41

Aluminum rod #1 is 1.0 m long with cross-section area 2.0 cm². Aluminum rod #2 is 2.0 m long with cross-section area 4.0 cm². Aluminum rod #3 is 3.0 m long with cross-section area 9.0 cm². If each rod has the same temperature difference applied across its ends, which rod has the greatest rate of transfer of energy between its ends?

(Multiple Choice)

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Question 42

How much heat (in kcal) must be removed to make ice at −10°C from 2 kg of water at 20°C? (The specific heat of ice is 0.50 cal/g⋅°C.)

(Multiple Choice)

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Question 43

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. Sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. Which one, if either is correct?

(Multiple Choice)

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Question 44

In an isovolumetric process

(Multiple Choice)

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Question 45

A 5-g coin is dropped from a 300-m building. If it reaches a terminal velocity of 45 m/s, and the rest of the energy is converted to heating the coin, what is the change in temperature (in °C) of the coin? (The specific heat of copper is 387 J/kg⋅°C.)

(Multiple Choice)

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Question 46

In braking an automobile, the friction between the brake drums and brake shoes converts the car's kinetic energy into heat. If a 1 500-kg automobile traveling at 30 m/s brakes to a halt, how much does the temperature rise in each of the four 8.0-kg brake drums? (The specific heat of each iron brake drum is 448 J/kg⋅°C).

(Short Answer)

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Question 47

An 8 000-kg aluminum flagpole 100-m long is heated by the sun from a temperature of 10°C to 20°C. Find the heat transferred (in J) to the aluminum if the specific heat of aluminum is 0.215 cal/g⋅°C.

(Multiple Choice)

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Question 48

If a person in Alaska were locked out of his house on a day when the temperature outside was −40°C, his thick clothing would mostly reduce the loss of thermal energy by

(Multiple Choice)

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Question 49

A styrofoam container used as a picnic cooler contains a block of ice at 0°C. If 225 grams of ice melts in 1 hour, how much heat energy per second is passing through the walls of the container? (The heat of fusion of ice is 3.33 × 10⁵ J/kg).

(Short Answer)

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Question 50

Which of the following substances has the greatest specific heat?

(Multiple Choice)

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Question 51

How much heat (in kilocalories) is needed to convert 1.00 kg of ice at 0°C into steam at 100°C?

(Multiple Choice)

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Question 52

In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct?

(Multiple Choice)

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Question 53

100 grams of liquid nitrogen at 77 K is stirred into a beaker containing 200 grams of 5°C water. If the nitrogen leaves the solution as soon as it turns to gas, how much water freezes? (The heat of evaporation of nitrogen is 6.09 cal/gram and the heat of fusion of water is 80 cal/gram.)

(Short Answer)

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Question 54

How much heat, in joules, is required to convert 1.00 kg of ice at 0°C into steam at 100°C? (L_ice = 333 J/g; L_steam = 2.26 × 10³ J/g.)

(Multiple Choice)

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Question 55

The work done in the expansion from an initial to a final state

(Multiple Choice)

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Question 56

A 5-kg piece of lead (specific heat 0.03 cal/g⋅°C) having a temperature of 80°C is added to 500 g of water having a temperature of 20°C. What is the final equilibrium temperature (in °C) of the system?

(Multiple Choice)

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Question 57

Gas in a container expands at a constant pressure of 3 atm. Find the work done (in J) by the gas if the initial volume is 5 liters and the final volume is 10 liters.

(Multiple Choice)

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Question 58

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft²⋅h) if the R values are 1.93 and 8.7 ft²⋅°F⋅h/BTU, respectively.

(Multiple Choice)

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Question 59

Star A has a radius of 200 000 km and a surface temperature of 6 000 K. Star B has a radius of 400 000 km and a surface temperature of 3 000 K. The emissivity of both stars is the same. What is the ratio of the rate of energy radiated by Star A to that of Star B?

(Short Answer)

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Question 60

Showing 41 - 60 of 61

Exam 20: The First Law of Thermodynamics

How much heat (in kcal) must be removed to make ice at −10°C from 2 kg of water at 20°C? (The specific heat of ice is 0.50 cal/g⋅°C.)

In an isovolumetric process

A 5-g coin is dropped from a 300-m building. If it reaches a terminal velocity of 45 m/s, and the rest of the energy is converted to heating the coin, what is the change in temperature (in °C) of the coin? (The specific heat of copper is 387 J/kg⋅°C.)

An 8 000-kg aluminum flagpole 100-m long is heated by the sun from a temperature of 10°C to 20°C. Find the heat transferred (in J) to the aluminum if the specific heat of aluminum is 0.215 cal/g⋅°C.

If a person in Alaska were locked out of his house on a day when the temperature outside was −40°C, his thick clothing would mostly reduce the loss of thermal energy by

A styrofoam container used as a picnic cooler contains a block of ice at 0°C. If 225 grams of ice melts in 1 hour, how much heat energy per second is passing through the walls of the container? (The heat of fusion of ice is 3.33 × 105 J/kg).

Which of the following substances has the greatest specific heat?

How much heat (in kilocalories) is needed to convert 1.00 kg of ice at 0°C into steam at 100°C?

In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct?

100 grams of liquid nitrogen at 77 K is stirred into a beaker containing 200 grams of 5°C water. If the nitrogen leaves the solution as soon as it turns to gas, how much water freezes? (The heat of evaporation of nitrogen is 6.09 cal/gram and the heat of fusion of water is 80 cal/gram.)

How much heat, in joules, is required to convert 1.00 kg of ice at 0°C into steam at 100°C? (Lice = 333 J/g; Lsteam = 2.26 × 103 J/g.)

The work done in the expansion from an initial to a final state

A 5-kg piece of lead (specific heat 0.03 cal/g⋅°C) having a temperature of 80°C is added to 500 g of water having a temperature of 20°C. What is the final equilibrium temperature (in °C) of the system?

Gas in a container expands at a constant pressure of 3 atm. Find the work done (in J) by the gas if the initial volume is 5 liters and the final volume is 10 liters.

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft2⋅h) if the R values are 1.93 and 8.7 ft2⋅°F⋅h/BTU, respectively.

Star A has a radius of 200 000 km and a surface temperature of 6 000 K. Star B has a radius of 400 000 km and a surface temperature of 3 000 K. The emissivity of both stars is the same. What is the ratio of the rate of energy radiated by Star A to that of Star B?

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A styrofoam container used as a picnic cooler contains a block of ice at 0°C. If 225 grams of ice melts in 1 hour, how much heat energy per second is passing through the walls of the container? (The heat of fusion of ice is 3.33 × 10⁵ J/kg).

How much heat, in joules, is required to convert 1.00 kg of ice at 0°C into steam at 100°C? (L_ice = 333 J/g; L_steam = 2.26 × 10³ J/g.)

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft²⋅h) if the R values are 1.93 and 8.7 ft²⋅°F⋅h/BTU, respectively.