A recipe asks for a teensy cake to be cooked on High for 70 secs in a 950 watt microwave.
What temperature would 'High' be? like in Celsius or Farenhite
It is impossible to convert Microwaves into Celsius or Fahrenheit.
Temperature is a measure of the average translational kinetic energy of the molecules of a system. Heat is commonly expressed in either of two units: the calorie, an older metric unit, and the British thermal unit (Btu), an English unit commonly used in the United States.
Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent 'energy per unit time'. For example, when a light bulb with a power rating of 100W is turned on for one hour, the energy used is 100 watt hours (W.
Microwaves are essentially radiation bombarding your food and causing the water molecules inside to get excited/vibrate, this in turn causes heat (Think rubbing your hands together).
If you are told to put something in a Microwave oven for 70 seconds, it is just a tried and tested method of getting the food to the correct internal temperature. You can't compare it to a standard oven.
This chart displays Watts with the corresponding temperature. This is not a conversion table but the temperature measured by heating 300ml water in a Samsung Microwave on different Watts / timings. I hope this helps
1 minute | 2 minutes | 3 minutes
100W : 35C/95F | 37C/98.6F | 40.8C /105.4F
180W : 37.4C/99.3F | 44C/111.2F | 47C/116.4F
300W : 43C/109.4F | 49.5C/121.1F | 59.7C/139.4F
450W : 48.5C/119.3F | 62.2C/143.9F | 74.8C/166.6F
600W : 54.4C/129.9F | 76.7C/170F | 90.3C/194.5F
800W : 60.2C/140.3F | 87.8C/190F | 100.6C/213F
I assume you mean what temperature would your food be after microwaving it? It depends on the food.
A microwave isn't getting hot like an oven does. It shoots microwaves at your food which causes the food to heat up a certain amount. The amount it heats up depends a lot on its water content, mass, etc.
A microwave is going to transmit a fixed amount of energy to your food in a given time frame. This energy will be converted to heat. However since its a fixed amount of energy it depends on what is receiving the energy that determines how much its heated up. A 100 pound steak will rise in temperature much less than the 1 pound steak because there is more of the 100 pound steak to heat up.
I've been using the following basic guidelines, but I do feel the need to gather more accurate information so will be following up with scientific method.
100% - - - - -Hi - - - - -425-500F
70% - - - - MdHi- - - - -350F
50% - - - - -Md - - - - -300F
30% - - - - -Lo - - - - -225F
10% - - - - -Wm - - - - -150F
Converting from oven to microwave oven needs time adjustment by 75%. In other words, instead of cooking for 1 hour you nuke it for ~15min.
I've had good luck with this. My microwave was manufactured to be 1050 Watts, but I'm not sure that is helping me so I'll need to be checking it's actual output with 1 liter of water nuked on high 2:03 and then measuring the temperature between 70F and after result. Then multiplying that by 35 should get acceptably near the wattage. At least, as we used to say in the military, "close enough for government work".
A recipe that says "70 seconds on high in a 950 Watt microwave" wants exactly that: put it in a 950W microwave for 70 seconds, at full power setting. The recipe author already worried about how hot or done the food is supposed to get from these settings; if you adjust the recipe (including doubling or halving), or use a weaker or stronger microwave, you have to estimate how much to adjust the cooking time.
the temp chart listed above is a good foundation to understanding the rate at which the material, in this case water, is being heated up. over-cooking food is all too common and has a high probability of creating carcinogens. with water there is theoretically minimal chance of such mutations.
a slow ramp up thermally helps to cook evenly an reduce the chance of internal and external burns, physiologically speaking. *to answer the question of watts vs working temp, only experience can put things into perspective unless your a design engineer working at a microwave manufacturer.
cook a simple muffin or biscuit that has a relatively low mass/density at 30% power level. fyi, power levels on a microwave are typically duty-cycle base so 30% is still cooking at full power but only 30% of the time. think slow cooker, yes its a long wait but the results make it worth the time.
another thing to consider is that microwave ovens are notorious for uneven cooking, especially on high (100% duty-cycle). lower power level gives the thermal intensity zones time to propagate throughout the material being heated. one could think of it as thermal reaction time.
**a better question might be what is the energy/thermal density of various microwave oven power ratings.