Assertion If temperature is increased, fundamental frequency of an close pipe will increase. Reason By…
Assertion If temperature is increased, fundamental frequency of an close pipe will increase.
Reason By increasing the temperature, speed of sound wave will increase.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct.
Solution
For a pipe with fundamental frequency $f$ (closed at one end) $f=\dfrac{v}{4l}$.
The speed of sound in a gas $v=\sqrt{\dfrac{\gamma RT}{M}}$.
Hence $f\propto v\propto\sqrt{T}$, i.e. frequency increases with temperature.
Both Assertion and Reason are true and the Reason (dependence of $v$ on $T$) explains the Assertion.