Correct Answer - Option 1 : -40°
CONCEPT:
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Temperature: It is the measure of the degree of hotness and coldness of a body.
- The SI unit of temperature is Kelvin (K).
- The various temperature scales commonly used are Celsius (C), Kelvin (K), Fahrenheit (F), and Rankine (Ra).
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Celsius: It has 100 degrees between the freezing and boiling points of water.
- Here 0° represents the freezing point and 100° represents the boiling point. In many countries, celsius is used to communicate day to day temperatures.
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Fahrenheit: The Fahrenheit scale was proposed by physicist Daniel Gabriel Fahrenheit in 1724.
- This scale is primarily used in the United States and some Caribbean countries to communicate day to day temperatures.
The temperature T in degrees Fahrenheit (°F) is equal to the temperature T in degrees Celsius (°C) times 9/5 plus 32:
\(°F={{9\over5}°C+32}\)
CALCULATION:
- The relation between the Celsius scale and Fahrenheit scale is given by
\(⇒ \frac{{F - 32}}{9} = \frac{C}{5} \)
By using the hit and trial method, suppose the -40° the centigrade and Fahrenheit scales of temperature are the same i.e., F = C
- The above equation can be written for C, then
\(⇒ \frac{{C - 32}}{9} = \frac{C}{5} \)
⇒ 5C - 160 = 9C
⇒ C = -40°
And for Fahrenheit scales,
\(⇒ \frac{{F - 32}}{9} = \frac{F}{5} \)
⇒ 5F - 160 = 9F
⇒ F = -40°
