Question

A celsius and a Fahrenheit thermometer are dipped in boiling water. The temperature of water is lowered until the Farenheit thermometer shows \(140^{\circ}\). What is the fall in temperature on the Celsius thermometer?

• A. \(60^{\circ}\) C
• B. \(40^{\circ}\) C
• C. \(50^{\circ}\) C
• D. \(80^{\circ}\) C

Hint:

Boiling water is 100 C or 212 F. Convert the fall in Fahrenheit degrees into Celsius degrees using the ratio 5 to 9.

Answer 1

The Correct Option is B

Step 1: Find the new Celsius reading.
$C = \dfrac{5}{9}(140 - 32) = \dfrac{5}{9}\times 108 = 60^\circ$C.

Step 2: Initial reading.
Boiling water reads $100^\circ$C.

Step 3: Fall.
$100 - 60 = 40^\circ$C.

Final Answer:
Option (B). \[ \boxed{40^{\circ}\text{C}} \]