At what temperature do the celcius and fahrenheit scale has the same numerical value?

Answer 1

For Celsius and Fahrenheit, the answer is -40°. Remember that the equation to convert Celsius to Fahrenheit is:

C = (9/5 * F) + 32

If we want C = F, then:

C = (9/5 * C) + 32
C - 32 = 9/5 * C
-32 = 4/5 * C
(5/4) * -32 = C = -40 = F

The Fahrenheit scale can also have an equivalent point with Kelvin, as deflagrated mentioned above:

K = C + 273.16 = [5/9 * (F-32)] + 273.16

If we want K = F, then:

K = [5/9 * (K-32)] + 273.16
K = (5/9 * K) - (5/9 * 32) + 273.16
4/9 * K = -(5/9 * 32) + 273.16
4/9 * K = -17.78 + 273.16 = 255.38

K = F = 574.61°

The Kelvin (K) scale is related to the Celsius scale, but the zero point, instead of being at the freezing point of water, is based on the extrapolated value for Absolute Zero -- the temperature at which all atomic & molecular motions cease. 0°K = -273.16°C.

For the Fahrenheit scale, there is an equivalent absolute scale called the Rankin (R) scale. 0° Rankin = -459.69°F

The absolute scales, Kelvin and Rankin, are only equal at 0°. For every degree increase in K, you increase R by 1.8°, so they will never be equal again until you reach infinity.

So, the only possible point at which all four of the temperature scales can possibly be equal is at infinity.

Answer 2

- 40

Answer 3

http://www.worldwidemetric.com/metcal.htm

Answer 4

-40

Doug