Wave Motion 4 Question 12
12. A copper wire is held at the two ends by rigid supports. At $30^{\circ} C$, the wire is just taut, with negligible tension. Find the speed of transverse waves in this wire at $10^{\circ} C$.
Given, Young modulus of copper $=1.3 \times 10^{11} N / m^{2}$. Coefficient of linear expansion of copper $=1.7 \times 10^{-5}{ }^{\circ} C^{-1}$. Density of copper $=9 \times 10^{3} kg / m^{3}$.
$(1979,4 M)$
apparent frequency of the source when it is moving away from the observer after crossing him? (Take, velocity of sound in air is $350 m / s$ )
(2019 Main, 10 April II)
(a) $807 Hz$
(b) $1143 Hz$
(c) $750 Hz$
(d) $857 Hz$
Show Answer
Answer:
Correct Answer: 12. (a)
Solution:
- Using the formula $f^{\prime}=f\left(\frac{v+v _0}{v}\right)$
we get, $\quad 5.5=5\left(\frac{v+v _A}{v}\right)$
and
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