Burning Calories by radiation (Stefan-Boltzman law)

AI Thread Summary
To determine how long it takes to radiate away 290 Calories from an ice cream cone using the Stefan-Boltzmann law, the user needs to calculate the power output based on body temperature, air temperature, emissivity, and surface area. The formula for power (P) involves the Stefan-Boltzmann constant and requires accurate temperature measurements in Kelvin. The user is struggling to connect the calculated power to time, needing clarification on how to derive time from the energy and power relationship. The discussion emphasizes the importance of correctly applying Stefan's law rather than just using the basic definition of power. Understanding these concepts is crucial for solving the problem effectively.
fordy314
Messages
6
Reaction score
0

Homework Statement


An ice cream cone has 290 Calories. Assuming the temperature of your skin is 32.7 C and the temperature of the air is 19.9 C, how long (hours) will it take to radiate away the energy of the ice cream cone. The emissivity of the average body is 0.915 and the average surface area of your skin is 1.25 m2.


Homework Equations


Stefan's law to get Watts
P=(J/Δt)
Q=mCΔT


The Attempt at a Solution


I'm all set with just plugging in the numbers into Stefan's Law to get watts, I'm having trouble trying to figure out how to get from watts to time though. All I can think of is

P=(J/Δt)=(Q/Δt) and Q=mCΔT, but I don't have enough information to solve for Q. Any help on this?

Thanks.
 
Physics news on Phys.org
You need Stefan-Boltzman law.
What you wrote is just the definition of power (P=Energy/time) and not Stefan's law.
 
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »

Similar threads

Calculate the Mass of Ice cubes needed to cool a soft drink
Replies
10
Views
3K
Why is the Stefan-Boltzman formula for this problem like this?
Replies
10
Views
3K
How Does Newton's Law of Cooling Affect Heat Loss Calculations?
Replies
2
Views
2K
Power Radiated From a Copper Cube
Replies
3
Views
783
Check my answer for power output question
Replies
9
Views
2K
Rate body temperature increases given rate of heat transfer?
Replies
1
Views
7K
Stefan-Boltzman Law Proof with Regards to Solar Radiation
Replies
4
Views
4K
Finding the final temperature when steam and ice are mixed
Replies
26
Views
33K
Find the temperature increase of a rotating disk
Replies
1
Views
1K
Quantity of heat, phase change of ice to water
Replies
7
Views
3K

Hot Threads

Recent Insights

Back
Top