MCQ
Audio signal cannot be transmitted because
  • A
    The signal has more noise
  • B
    The signal cannot be amplified for distance communication
  • C
    The transmitting antenna length is very small to design
  • The transmitting antenna length is very large and impracticable

Answer

Correct option: D.
The transmitting antenna length is very large and impracticable
d
(d) Following are the problems which are faced while transmitting audio signals directly.

$(i)$ These signals are relatively of short range.

$(ii)$ If every body started transmitting these low frequency signals directly, mutual interference will render all of them ineffective.

$(iii)$ Size of antenna required for their efficient radiation would be larger $i.e$. about $75 km.$

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

A convex lens makes a real image $4 cm$ long on a screen. When the lens is shifted to a new position without disturbing the object, we again get a real image on the screen which is $16 cm$ tall. The length of the object must be.......$cm$
In an elastic collision between disks $A$ and $B$ of equal mass but unequal radii, $A$ moves along the $x$ -axis and $B$ is stationary before impact. Which of the following is possible after impact?
A galvanometer having a coil resistance of $30\,\Omega $ shows full scale deflection when a current of $2\,A$ passes through it. It can be converted into an ammeter to read currents upto $10\,A$ by
A glass tube of uniform internal radius ( $\mathrm{r}$ ) has a valve separating the two identical ends. Initially, the valve is in a tightly closed position. End $1$ has a hemispherical soap bubble of radius $\mathrm{r}$. End $2$ has sub-hemispherical soap bubble as shown in figure. Just after opening the valve,

Figure: $Image$

The figure shows the position - time $(x-t)$ graph of one-dimensional motion of the body of mass $0.4\; kg$. The magnitude of each impulse is 
A long cylindrical vessel is half filled with a liquid. When the vessel is rotated about its own vertical axis, the liquid rises up near the wall. If the radius of vessel is $5\,cm$ and its rotational speed is $2$ rotations per second, then the difference in the heights between the centre and the sides, in $cm,$ will be
A closed organ pipe has a frequency $'n'$. If its length is doubled and radius is halved, its  frequency nearly becomes-
The angular speed of truck wheel is increased from $900\, rpm$ to $2460\, rpm$ in $26$ seconds. The number of revolutions by the truck engine during this time is

(Assuming the acceleration to be uniform).

Product of the reaction is
$Assertion :$ The time-period of pendulum, on a satellite orbiting the earth is infinity.
$Reason :$ Time-period of a pendulum is inversely proportional to $\sqrt g$