Question

Assertion: The temperature at which centigrade and Fahrenheit thermometer read the same is $-40$ on each scale.
Reason: There is no relation between Fahrenheit and centigrade temperature scale.

• A. Both Assertion and Reason are correct and Reason is the correct explanation.
• B. Both Assertion and Reason are correct and Reason is not the correct explanation.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is C Assertion is correct but Reason is incorrect.

We know that,
$\frac{9}{5}C=F-32$
Let $T$ be the temperature where both the thermometers have same reading.
So, $\frac{9}{5}\times T=T-32$
$\Rightarrow \frac{4T}{5}=-32$
$\Rightarrow T=-{40}^{\circ }\text{C}$
Hence, Assertion is correct but Reason is incorrect.