Question
An observer starts moving with uniform acceleration $a$ toward a stationary sound source emitting a whistle of frequency $n.$ As the observer approaches source, the apparent frequency, heard by the observer varies with time as
✓
Answer
(b) For observer approaching a stationary source
$n' = \frac{{v + {v_0}}}{v}.n$ and given ${v_0} = at$==>$n' = \left( {\frac{{an}}{v}} \right)\;t + n$
this is the equation of straight line with positive intercept $n$ and positive slope $\left( {\frac{n}{v}} \right)$.
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 bob of mass $10$ $M$ is suspended through an inextensible string of length $l$. When the bob is at rest at the equilibrium position, two particles of mass $m$ each moving with velocity $u$ making an angle $60^o $ with the string strike and get simultaneously attached to the bob. What is the value of impulsive tension $(l)$ in the string during the impact ?
→In a transformer, numbers of turns in the primary are $140$ and that in the secondary are $280 .$ If current in primary is $4\, A ,$ then that in the secondary is. (in $A$)
→Which one of the following is the weakest kind of bonding in solids
A plano-convex lens of refractive index $1.5$ and radius of curvature $30 \;cm$ is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of the size of the object?
→The $(x, y)$ coordinates of the corners of a square plate are $(0, 0), (L, 0), (L, L)$ and $(0, L).$ The edges of the plate are clamped and transverse standing waves are set up in it. If $u(x, y)$ denotes the displacement of the plate at the point $(x, y)$ at some instant of time, the possible expression(s) for $u$ is(are) ($a =$ positive constant)
→A block of mass $0.1 \,kg$ is held against a wall by applying a horizontal force of $5\, N$ on the block. If the coefficient of friction between the block and the wall is $0.5$, the magnitude of the frictional force acting on the block is ........ $N$
→Lenz's law gives
Two persons $A$ and $B$, each carrying a source of sound of frequency $n$, are standing a few metres apart in a quiet field. $A$ starts moving towards $B$ with a speed $u$. If $v$ is the speed of sound, the number of beats heard per second by $A$ will be
→The recoil speed of a hydrogen atom after it emits a photon in going from $n =5$ state to $n =1$ state will be ..... $m/s$
→Keeping dissimilar poles of two magnets of equal pole strength and length same side, their time period will be