MCQ
Three waves of equal frequency having amplitudes $10\, \mu m, 4\, \mu m$ and $7\, \mu m$ arrive at a given point with successive phase difference of $\pi/2$. The amplitude of the resulting wave in $\mu m$ is given by
- A$7$
- B$6$
- ✓$5$
- D$4$
✓
Answer
Correct option: C.
$5$
c
Phase difference between $I$ and $III$ wave is $\pi$ rad
Phase difference between $I$ and $III$ wave is $\pi$ rad
so resulting is $10\, \mu \mathrm{m}-7\, \mu \mathrm{m}=3\, \mu \mathrm{m}$ then amplitude of resultant wave is
$\sqrt{(4)^{2}+(3)^{2}}=5\, \mu m$
$O R$
$\Rightarrow A_{r}=\sqrt{(3)^{2}+(4)^{2}}=5$
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