MCQ
The phase difference between two points separated by $0.8 m$ in a wave of frequency is $120 Hz$ is $\frac{\pi }{2}.$ The velocity of wave is ..... $m/s$
- A$720$
- ✓$384$
- C$250$
- D$1 $
✓
Answer
Correct option: B.
$384$
b
(b) Phase difference $ = \frac{{2\pi }}{\lambda } \times$ path difference
(b) Phase difference $ = \frac{{2\pi }}{\lambda } \times$ path difference
$ \Rightarrow \frac{\pi }{2} = \frac{{2\pi }}{\lambda } \times 0.8$
$ \Rightarrow \lambda = 4 \times 0.8 = 3.2\,m$
Velocity $v = n\lambda $$ = 120 \times 3.2 = 384\,m/s.$
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
The number of significant figures in the measured value $4.700 \,m$ is the same as that in the value ....... $m$
→The resistances of the platinum wire of a platinum resistance thermometer at the ice point and steam point are $8 \Omega$ and $10 \Omega$ respectively. After inserting in a hot bath of temperature $400^{\circ} \mathrm{C}$, the resistance of platinum wire is:
→Tesla is a unit for measuring
Consider a solid sphere of radius $\mathrm{R}$ and mass density $\rho(\mathrm{r})=\rho_{0}\left(1-\frac{\mathrm{r}^{2}}{\mathrm{R}^{2}}\right), 0<\mathrm{r} \leq \mathrm{R} .$ The minimum density of a liquid in which it will float is
→Nitriles are reduced to corresponding imine with stannous chloride in presence of hydrochloric acid, which on hydrolysis give corresponding aldehyde, this reaction is called
A vessel contains $16 \,g$ of hydrogen and $128 \,g$ of oxygen at standard temperature and pressure. The volume of the vessel in $cm ^{3}$ is
→When light travels from glass to air, the incident angle is ${\theta _1}$ and the refracted angle is ${\theta _2}$. The true relation is
→A thin wire of length $2\,m$ is placed perpendicular to the $x-y$ plane. It is moved with velocity $\overrightarrow v = \left( {2\hat i + 3\hat j + \hat k} \right)\,m/s$ through a region of magnetic induction $\overrightarrow B = \left( {\hat i + 2\hat j} \right)\,wb/{m^2} .$ The potential difference induced between the ends of the wire is......$volts$
→The wavelength associated with an electron accelerated through a potential difference of $100 V$ is nearly .............. $\mathop {\rm{A}}\limits^o $
→Four point $+ve$ charges of same magnitude $(Q)$ are placed at four corners of a rigid square frame as shown in figure. The plane of the frame is perpendicular to $Z-$ axis. If a $ -ve$ point charge is placed at a distance $z$ away from centre along axis $(z << L )$ then
→