Does the required time to heat a body from 20°C to 40°C the same as from 40°C to 60°C?
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The energy required to heat something is the temperature difference multiplied by the mass multiplied by the thermal capacity.
Thermal capacity is technically temperature dependent, so heating a 40°C object by 1K takes a different amount of energy than heating that same object by 1K at 0°C, but for most materials and normal temperature ranges it’s fairly accurate to just assume a constant thermal capacity.
So the **energy** required to do the heating is (more or less) the same in either case.
The **time** depends on how the thing is being heated. If you have a constant power source that’s heating the body, and we neglect any losses, then yes, both heating phases would take the same amount of time.
If you instead are heating the object using something at a constant temperature (so for example placing it inside a 100°C hot room), then the power absorbed by the object is higher when it’s cold, since thermal power transfer is proportional to temperature difference, so a 40°C object in a 100°C room will heat to 41°C faster than that same object will heat from 60°C to 61°C, so in that case the second heating portion would take longer than the first.
The energy required to heat something is the temperature difference multiplied by the mass multiplied by the thermal capacity.
Thermal capacity is technically temperature dependent, so heating a 40°C object by 1K takes a different amount of energy than heating that same object by 1K at 0°C, but for most materials and normal temperature ranges it’s fairly accurate to just assume a constant thermal capacity.
So the **energy** required to do the heating is (more or less) the same in either case.
The **time** depends on how the thing is being heated. If you have a constant power source that’s heating the body, and we neglect any losses, then yes, both heating phases would take the same amount of time.
If you instead are heating the object using something at a constant temperature (so for example placing it inside a 100°C hot room), then the power absorbed by the object is higher when it’s cold, since thermal power transfer is proportional to temperature difference, so a 40°C object in a 100°C room will heat to 41°C faster than that same object will heat from 60°C to 61°C, so in that case the second heating portion would take longer than the first.
The energy required to heat something is the temperature difference multiplied by the mass multiplied by the thermal capacity.
Thermal capacity is technically temperature dependent, so heating a 40°C object by 1K takes a different amount of energy than heating that same object by 1K at 0°C, but for most materials and normal temperature ranges it’s fairly accurate to just assume a constant thermal capacity.
So the **energy** required to do the heating is (more or less) the same in either case.
The **time** depends on how the thing is being heated. If you have a constant power source that’s heating the body, and we neglect any losses, then yes, both heating phases would take the same amount of time.
If you instead are heating the object using something at a constant temperature (so for example placing it inside a 100°C hot room), then the power absorbed by the object is higher when it’s cold, since thermal power transfer is proportional to temperature difference, so a 40°C object in a 100°C room will heat to 41°C faster than that same object will heat from 60°C to 61°C, so in that case the second heating portion would take longer than the first.
It is better to compare this in terms of energy instead of time.
To keep it simple, say that to heat a bucket of water from 20C to 40C you need one unit of energy.
The amount you will need to do the same from 40C to 60C will depend on the specific heat of the water. This is a physical quantity that depends on the type of material and the current temperature.
Keeping the example for water, the specific heat increases slightly with temperature, meaning that the hotter your water currently is, the more energy you will need to keep heating it. So to go from 40 to 60 you will need one unit of energy plus X.
If the output of energy you have in terms of time is constant (ie, how much energy you can give in a given time), then the time to heat up from 20 to 40 will be shorter than to heat up from 40 to 60. If you can, however, just increase the amount of energy you are supplying, then the overall time doesn’t have much meaning.
It is better to compare this in terms of energy instead of time.
To keep it simple, say that to heat a bucket of water from 20C to 40C you need one unit of energy.
The amount you will need to do the same from 40C to 60C will depend on the specific heat of the water. This is a physical quantity that depends on the type of material and the current temperature.
Keeping the example for water, the specific heat increases slightly with temperature, meaning that the hotter your water currently is, the more energy you will need to keep heating it. So to go from 40 to 60 you will need one unit of energy plus X.
If the output of energy you have in terms of time is constant (ie, how much energy you can give in a given time), then the time to heat up from 20 to 40 will be shorter than to heat up from 40 to 60. If you can, however, just increase the amount of energy you are supplying, then the overall time doesn’t have much meaning.
The short answer is “not in general, but in specific cases maybe”. The question isn’t specific enough to go into details, but if you give more information I can elaborate. How is it being heated? Is there a phase change? What material is it?
The short answer is “not in general, but in specific cases maybe”. The question isn’t specific enough to go into details, but if you give more information I can elaborate. How is it being heated? Is there a phase change? What material is it?
It is better to compare this in terms of energy instead of time.
To keep it simple, say that to heat a bucket of water from 20C to 40C you need one unit of energy.
The amount you will need to do the same from 40C to 60C will depend on the specific heat of the water. This is a physical quantity that depends on the type of material and the current temperature.
Keeping the example for water, the specific heat increases slightly with temperature, meaning that the hotter your water currently is, the more energy you will need to keep heating it. So to go from 40 to 60 you will need one unit of energy plus X.
If the output of energy you have in terms of time is constant (ie, how much energy you can give in a given time), then the time to heat up from 20 to 40 will be shorter than to heat up from 40 to 60. If you can, however, just increase the amount of energy you are supplying, then the overall time doesn’t have much meaning.
Yes. The amount of energy to go up one degree doesn’t change much on temperature.
There are 2 broad exceptions. If something melts or boils in that temperature range then that’s not going to work. Also the hotter something gets the faster it loses heat to the surrounding environment, so if you lose heat too fast it’s going to be harder to warm something.
The short answer is “not in general, but in specific cases maybe”. The question isn’t specific enough to go into details, but if you give more information I can elaborate. How is it being heated? Is there a phase change? What material is it?
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