Physics Waves PMDC 2020
PMDC Verified Question 91 of 125
The speed of sound in air is 332 m/s. The speed of sound at 22\( ^\circ\text{C} \) will be:
A
345.2m/s
B
340 m/s
C
350m/s
D
330 m/s
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: 345.2m/s
Concept:

The speed of sound in air increases linearly with an increase in Celsius temperature.

Formula:

$$ v_t = v_0 + 0.61t $$

Solution:

  • Here, \( v_0 \) (speed at 0\( ^\circ\text{C} \)) is given as 332 m/s, and temperature \( t = 22^\circ\text{C} \).


  • Calculate the increment: \( 0.61 \times 22 \approx 13.42 \text{ m/s} \).


  • Add this increment to the baseline speed: \( v_{22} = 332 + 13.42 = 345.42 \text{ m/s} \).


  • Option A (345.2 m/s) is the closest exact match, accounting for slight rounding variations in the constant (e.g., using 0.6 m/s per degree yields 345.2).


Why other options are incorrect:

Failing to multiply by the 0.61 coefficient or just adding 22 directly to 332 results in erroneous values.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

Previous Question All Waves MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App