A source of frequency gives 5 beats/second when sounded with a so… - Vidyadip

MCQ

A source of frequency $\nu$ gives $5$ beats/second when sounded with a source of frequency $200 \;Hz$. The second harmonic of frequency $2\nu$ of source gives $10$ beats/second when sounded with a source of frequency $420\; Hz$. The value of $v$ is .... $Hz$

A
$195$
✓
$205$
C
$200$
D
$210$

✓

Answer

Correct option: B.

$205$

b
(b) Initially number of beats per second $= 5$

$ \therefore$ Frequency of pipe $= 200 \pm \,5 = 195 Hz$ or $205 Hz$ ...$(i)$

Frequency of second harmonics of the pipe $= 2n$

and number of beats in this case $= 10$

$ \therefore$ $2n = 420 \pm \, 10 $

==> $410 Hz$ or $430 Hz$

==> $n = 205 Hz$ or $215 Hz$ ... $(ii)$

From equation $(i)$ and $(ii)$ it is clear that $n = 205 Hz$

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

Explore more

JEE STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

The work function of aluminium is $4.2eV.$ If two photons, each of energy $3.5 eV$strike an electron of aluminium, then emission of electrons will be

If maximum energy is stored in capacitor at $t =0$ then find the time after which current in the circuit will be maximum.

The molar specific heat at constant pressure for a monoatomic gas is

One mole of an ideal gas at $300 \mathrm{~K}$ in thermal contact with surroundings expands isothermally from $1.0 \mathrm{~L}$ to $2.0 \mathrm{~L}$ against a constant pressure of $3.0 \mathrm{~atm}$. In this process, the change in entropy of surroundings $\left(\Delta S_{\text {surr }}\right)$ in $\mathrm{J} \mathrm{K}^{-1}$ is $(1 \mathrm{~L} \mathrm{~atm}=101.3 \mathrm{~J})$

A block of mass $50 \,kg$ can slide on a rough horizontal surface. The coefficient of friction between the block and the surface is $0.6$. The least force of pull acting at an angle of $30^°$ to the upward drawn vertical which causes the block to just slide is ........ $N$

An ideal gas is made to undergo the cyclic process shown in the figure below. Let $\Delta W$ depict the work done, $\Delta U$ be the change in internal energy of the gas and $Q$ be the heat added to the gas. Sign of each of these three quantities for the whole cycle will be (0 refers to no change)

An electromagnetic wave is represented by the electric field $\vec E = {E_0}\hat n\,\sin \,\left[ {\omega t + \left( {6y - 8z} \right)} \right]$. Taking unit vectors in $x, y$ and $z$ directions to be $\hat i,\hat j,\hat k$ ,the direction of propogation $\hat s$, is

If the series limit of the Balmer series for hydrogen is $2700\ Å$. Calculate the atomic no. of the element which gives $X-$ray wavelength of $K_{\alpha}$ line as $1.0\ Å$. $z =..........$

A radioactive nucleus ${ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X}$ undergoes spontaneous decay in the sequence

${ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X} \rightarrow {}_{\mathrm{Z}-1}{\mathrm{B}} \rightarrow {}_{\mathrm{Z}-3 }\mathrm{C} \rightarrow {}_{\mathrm{Z}-2} \mathrm{D}$, where $\mathrm{Z}$ is the atomic number of element $X.$ The possible decay particles in the sequence are :

A moving coil galvanometer has a coil with $175\, turns$ and area $1\, cm^2$ It uses a torsion band of torsion constant $10^{-6}\, N\, -m/rad$. The coil is placed in a magnetic field $B$ parallel to its plane. The coil deflects by $10$ for a current of $1\, mA$. The value of $B$ (in Tesla) is approximately