When the sound wave returns to the machine, you can measure
how long it took to return.
(You may notice that it's working just like RADAR, which does the
same thing with radio waves instead of sound waves.)
Even if you know how long the sound took to get to the bottom and
return to the top, you can't DO anything with this information if you
don't know the SPEED of the sound through the water. Not only
the inventory of this machine, but anyone who uses it, has to know
the speed of the sound through water in order to use the round-trip
time to calculate the depth.
Answer : The temperature of the hot reservoir (in Kelvins) is 1128.18 K
Explanation :
Efficiency of carnot heat engine : It is the ratio of work done by the system to the system to the amount of heat transferred to the system at the higher temperature.
Formula used for efficiency of the heat engine.

where,
= efficiency = 0.780
= Temperature of hot reservoir = ?
= Temperature of cold reservoir = 
Now put all the given values in the above expression, we get:



Therefore, the temperature of the hot reservoir (in Kelvins) is 1128.18 K
Answer:
Explanation:
Given
charge of first body 
charge of second body 
Particle 1 is at origin and particle 2 is at 
third Particle which charge +q must be placed left of
because it will repel the q charge while
will attract it
suppose it is placed at a distance of x m








Answer
Wavelength= 30*20^8/30=10^7m
Explanation:
Velocity = frequency *wavelength
We're frequency=30HZ
Velocity of light= 3*10^8m/s
Wavelength= 30*20^8/30=10^7m
Explanation: