[3 Mark Question Answer]

Question 13 Marks

At what temperature, is the reading on the Celsius scale twice that on the Fahrenheit scale?

Answer

We know, $F =\frac{9 x C}{5}+32$.
When Fahrenheit reading is double than Celsius reading,
$ F =2 C$
$2 C =\frac{9 x C}{5}+32$
$2 C -32=\frac{9 C}{5}$
$5 \times(2 C -32)=9 C$
$10 C -160=9 C$
$10 C -9 C =160$
$C =160^{\circ} C$
Therefore, when the reading on the Celsius scale is $160^{\circ} C$,
the reading on the Fahrenheit scale will be $320^{\circ} F$.

View full question & answer→

Question 23 Marks

At what temperature will the reading on the Fahrenheit scale be double of that on the Celsius scale ?

Answer

Let reading on the Celsius scale $= x$
Let reading on the Fahrenheit scale $=2 x$
Using the formula,
$C=\frac{5}{9}(F-32)$
Substitute values of $C$ and $F$ by $x$ and $2 x$
$x=\frac{5}{9}(2 x-32)$
$x=\frac{10}{9} x-\frac{160}{9}$
$x-\frac{10}{9} x=\frac{-160}{9}$
$\frac{9 x-10 x}{9}=\frac{-160}{9}$
$-\frac{1 x}{9}=\frac{-160}{9} \times \frac{-9}{1}=160$
At $160^{\circ} C$, reading on the Fahrenheit scale will be double of that on the Celsius scale.

View full question & answer→

PHYSICS [3 Mark Question Answer]

Test yourself on this topic