Q. The temperature, at which Centigrade and Fahrenheit scales give the same reading is
A) -40${^\circ}$
B) 40${^\circ}$
C) -30${^\circ}$
D) 30${^\circ}$
Explanation
(a) Let the common temperature is $x$ on both scales.
$\frac{C}{5}\ = \frac{F - 32}{9}$
Put $C = F = x$
$\ \ \therefore\ \ \ \ \ \frac{x}{5} = \frac{x - 32}{9}$
Or $9x = 5x - 160$
Or $4x = - 160$
$\ \therefore\ \ \ \ \ \ \ \ x = - 40℃$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.