Thermodynamics B/C

[smayya337]

What type of heat engine can a hurricane be likened to? What is its source of heat and where does it exhaust the heat to? Assuming typical temperatures, pressures, etc. for the source of heat and exhaust (you may want to look up these typical values), what is its theoretical maximum efficiency?

I had to ask you for help on this (Click to Show Hidden Text)

A hurricane is a Carnot engine, since there's no fuel, just heat. Its source of heat is the tropical water, and its exhaust is the atmosphere. The temperature at the water's surface is 20°C and the temperature at the top of the hurricane is -40°C, giving an efficiency of 79.53%. Then you came over and reminded me that you need to subtract the value from one, so the actual Carnot efficiency is 20.47%.

[mjcox2000]

What type of heat engine can a hurricane be likened to? What is its source of heat and where does it exhaust the heat to? Assuming typical temperatures, pressures, etc. for the source of heat and exhaust (you may want to look up these typical values), what is its theoretical maximum efficiency?

I had to ask you for help on this (Click to Show Hidden Text)

A hurricane is a Carnot engine, since there's no fuel, just heat. Its source of heat is the tropical water, and its exhaust is the atmosphere. The temperature at the water's surface is 20°C and the temperature at the top of the hurricane is -40°C, giving an efficiency of 79.53%. Then you came over and reminded me that you need to subtract the value from one, so the actual Carnot efficiency is 20.47%.

Than looks right and the values seem reasonable enough. Your turn!

[wec01]

What type of heat engine can a hurricane be likened to? What is its source of heat and where does it exhaust the heat to? Assuming typical temperatures, pressures, etc. for the source of heat and exhaust (you may want to look up these typical values), what is its theoretical maximum efficiency?

I had to ask you for help on this (Click to Show Hidden Text)

A hurricane is a Carnot engine, since there's no fuel, just heat. Its source of heat is the tropical water, and its exhaust is the atmosphere. The temperature at the water's surface is 20°C and the temperature at the top of the hurricane is -40°C, giving an efficiency of 79.53%. Then you came over and reminded me that you need to subtract the value from one, so the actual Carnot efficiency is 20.47%.

Than looks right and the values seem reasonable enough. Your turn!

Ah, yes. An earth science connection.

[smayya337]

1) Find the spectral radiance of a black-body, provided that the frequency of radiation is 700Hz and the temperature is 14000K.
2) Find the radiant exitance of a black surface at 0°C.

[wec01]

1) Find the spectral radiance of a black-body, provided that the frequency of radiation is 700Hz and the temperature is 14000K.
2) Find the radiant exitance of a black surface at 0°C.

Answers (Click to Show Hidden Text)

1) 2 x 10^-30 (1 sig fig)
2) 315 W/m^2 (3 sig figs)

[smayya337]

1) Find the spectral radiance of a black-body, provided that the frequency of radiation is 700Hz and the temperature is 14000K.
2) Find the radiant exitance of a black surface at 0°C.

Answers (Click to Show Hidden Text)

1) 2 x 10^-30 (1 sig fig)
2) 315 W/m^2 (3 sig figs)

You're correct!

[wec01]

Here is a relatively straightforward question:

A 100g ice cube at -10 degrees Celsius is added to 100g of water at 10 degrees Celsius.
1) What is the final state of the solution (phase of matter and temperature)?
2) Why doesn't the solution simply become a mixture of ice and water at 0 degrees Celsius?

[Crimesolver]

Here is a relatively straightforward question:

A 100g ice cube at -10 degrees Celsius is added to 100g of water at 10 degrees Celsius.
1) What is the final state of the solution (phase of matter and temperature)?
2) Why doesn't the solution simply become a mixture of ice and water at 0 degrees Celsius?

1) It is a liquid at 3.3 Celsius
2)This is because ice has a lower specific heat, which means it melts and heats up more easily.

[UTF-8 U+6211 U+662F]

Here is a relatively straightforward question:

A 100g ice cube at -10 degrees Celsius is added to 100g of water at 10 degrees Celsius.
1) What is the final state of the solution (phase of matter and temperature)?
2) Why doesn't the solution simply become a mixture of ice and water at 0 degrees Celsius?

Click to Show Answer

1) It is a liquid at 3.3 Celsius 

2)This is because ice has a lower specific heat, which means it melts and heats up more easily.

Reminder to use the

Click to Show Answer

 or [hide] tags for answers in case anyone wants to follow along

[Crimesolver]

Here is a relatively straightforward question:

A 100g ice cube at -10 degrees Celsius is added to 100g of water at 10 degrees Celsius.
1) What is the final state of the solution (phase of matter and temperature)?
2) Why doesn't the solution simply become a mixture of ice and water at 0 degrees Celsius?

Click to Show Answer

1) It is a liquid at 3.3 Celsius 

2)This is because ice has a lower specific heat, which means it melts and heats up more easily.

Reminder to use the

Click to Show Answer

 or [hide] tags for answers in case anyone wants to follow along

Ooof totally forgot, was excited that I kinda knew the answer to this one