MCQ
A second harmonic has to be generated in a string of length $l$ stretched between two rigid supports. The points where the string has to be plucked and touched are respectively
  • $\frac{l}{4}, \frac{l}{2}$
  • B
    $\frac{l}{4}, \frac{3l}{4}$
  • C
    $\frac{l}{2}, \frac{l}{2}$
  • D
    $\frac{l}{2}, \frac{3l}{4}$

Answer

Correct option: A.
$\frac{l}{4}, \frac{l}{2}$
a
(a)

In the $2^{\text {nd }}$ harmonic the shape of wave looks like.

The point of touching forms a node point of plucking forms an antinode. Hence, for $2^{\text {nd }}$ harmonic, we need to need wire touched at $\frac{l}{2}$ and pluck it at $\frac{l}{4}$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

In an $LCR$ circuit $R = 100$ ohm. When capacitance $C$ is removed, the current lags behind the voltage by $\pi /3$. When inductance $L$ is removed, the current leads the voltage by $\pi /3$. The impedance of the circuit is......$ohm$
In the context of Doppler effect in light, the term ‘red shift’ signifies
A particle of charge $1\  \mu C\  \&\  mass$ $1\  gm$ moving with a velocity of $4\  m/s$ is subjected to a uniform electric field of magnitude $300\  V/m$ for $10\  sec$. Then it's final speed cannot be.......$m/s$
The Doppler's effect is applicable for
The displacement y of a particle in a medium can be expressed as: $y = {10^{ - 6}}\sin (100t + 20x + \pi /4)m,$ where $t$ is in second and $x$ in meter. The speed of wave is ... $m/s$
$A$ uniform rod is fixed to a rotating turntable so that its lower end is on the axis of the turntable and it makes an angle of $20^o$ to the vertical. (The rod is thus rotating with uniform angular velocity about a vertical axis passing through one end.) If the turntable is rotating clockwise as seen from above. Is there a torque acting on it, and if so in what direction?
In the given figure, the value of $V_{0}$ will be $.....V$.
A boy whose mass is $50\,kg$ stands on a spring balance inside a lift. The lift starts to ascent with an acceleration of $2\,m{s^{ - 2}}.$ The reading of the machine or balance $(g = 10\,m{s^{ - 2 }})$ is ........ $kg$
In a $p-n$ junction diode, change in temperature due to heating
A liquid boils when its vapour pressure equals