Q. A centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers $140^{o}$. What is the fall in temperature as registered by the Centigrade thermometer
A) $30^{o}$
B) $40^{o}$
C) $60^{o}$
D) $80^{o}$
Explanation
(b) $\frac{\mathrm{\Delta}T_{C}}{100} = \frac{\mathrm{\Delta}T_{F}}{180} = \frac{212 - 140}{180}$
$i.e.,\ \mathrm{\Delta}T_{C} = 100 \times \frac{72}{180} = 40℃$
$\therefore$ Fall in temperature $= 40^{o}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.