Question 640: Thermodynamics & KTG

Question

A centigrade and Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit temperature observed is $140^{\circ} \mathrm{F}$. At that time the temperature registered by the centigrade thermometer is

Accepted Answer

The relation between Celsius (centigrade, $C$) and Fahrenheit ($F$) is:
$ F = \frac{9}{5}C + 32 $
Given:
$F = 140^\circ \mathrm{F}$
Let the temperature registered by the centigrade thermometer be $C^{\circ} \mathrm{C}$.
Substitute the value of $F$:
$ 140 = \frac{9}{5}C + 32 $
Subtract $32$ from both sides:
$ 140 - 32 = \frac{9}{5}C $
$ 108 = \frac{9}{5}C $
Multiply both sides by $5$:
$ 540 = 9C $
Divide both sides by $9$:
$ C = \frac{540}{9} = 60 $
So, the temperature on the centigrade thermometer will be $60^\circ \mathrm{C}$.
Answer:
Option B
$60^{\circ} \mathrm{C}$

Answer

$80^{\circ} \mathrm{C}$

Answer

$60^{\circ} \mathrm{C}$

Answer

$40^{\circ} \mathrm{C}$

Answer

$20^{\circ} \mathrm{C}$

Thermodynamics & KTG

A centigrade and Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit temperature observed is 140^{\circ} \mathrm{F}. At that time the temperature registered by the centigrade thermometer is

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