MCQ
The wavelength of a particle is $99 cm$ and that of other is $100 cm$ Speed of sound is $396 m/s$. The number of beats heard is
- ✓$4$
- B$5$
- C$1$
- D$8$
✓
Answer
Correct option: A.
$4$
a
(a) $\Delta n = v\left[ {\frac{1}{{{\lambda _1}}} - \frac{1}{{{\lambda _2}}}} \right] = 396\,\left[ {\frac{1}{{0.99}} - \frac{1}{1}} \right] = 3.96 \approx 4.$
(a) $\Delta n = v\left[ {\frac{1}{{{\lambda _1}}} - \frac{1}{{{\lambda _2}}}} \right] = 396\,\left[ {\frac{1}{{0.99}} - \frac{1}{1}} \right] = 3.96 \approx 4.$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A billiard table whose length and width are as shown in the figure. $A$ ball is placed at point $A$. At what angle ‘$\theta $ ’the ball be projected so that after colliding with two walls, the ball will fall in the pocket $B$ .Assume that all collisions are perfectly elastic (neglect friction)
→A satellite of mass $m$ is placed at a distance $r$ from the centre of earth (mass $M$). The mechanical energy of the satellite is
→The displacement y of a particle executing periodic motion is given by $y = 4{\cos ^2}(t/2)\sin (1000t)$. This expression may be considered to be a result of the superposition of ........... independent harmonic motions
→An $\alpha-$particle is bombarded on ${ }^{14}\mathrm{~N}$. As a result, a ${ }^{17}\mathrm{O}$ nucleus is formed and a particle is emitted. This particle is a:
→The mean distance between the atoms of iron is $3 \times {10^{ - 10}}m$ and interatomic force constant for iron is $7\,N\,/m$The Young’s modulus of elasticity for iron is
→The centripetal acceleration is given by
Two cars $S_1$ and $S_2$ are moving in coplanar concentric circular tracks in the opposite sense with the periods of revolution $3 \,min$ and $24 \,min$, respectively. At time $t=0$, the cars are farthest apart. Then, the two cars will be
→If a satellite of mass $400 \,kg$ revolves around the earth in an orbit with speed $200 \,m / s$ then its potential energy is .......... $MJ$
→A string of negligible thickness is wrapped several times around a cylinder kept on a rough horizontal surface. A man standing at a distance $1$ from the cylinder holds one end of the string and pulls the cylinder towards him. There is no slipping anywhere. The length of the string passed through the hand of the man while the cylinder reaches his hands is:
→Consider a compound slab consisting of two different materials having equal thickness and thermal conductivities $K$ and $2K$ respectively. The equivalent thermal conductivity of the slab is:
→