Answer:
A )
Explanation:
This change in frequency observation occur due to doppler effect
if the wave source moves,In the time between one wave peak being emitted and the next, the source will have moved so that the shells will no longer be concentric. The wavefronts will get closer together in front of the source as it travels and will be further apart behind it. (see the graph)
when the person standing still in front of the ambulance, he will observe a <em>higher frequency </em>than before as the source travels towards them.
The pitch we hear depends on the frequency of the sound wave.
A high frequency corresponds to a high pitch
as we hear a higher frequency , it makes the <em>pitch higher</em> too
Answer:4N
Explanation:
mass=4kg
Acceleration=1m/s^2
Force=mass x acceleration
Force=4 x 1
Force=4N
If the earth just doubles its size in an instant, the oxygen present in the atmosphere could be much larger. Due to these, we could theorize that insects could grow much larger because the size of their body is heavily dependent on the maximum amount of oxygen present in the atmosphere. Air pressure also increases thus those aerial enthusiasts would enjoy their professions.
Answer:B
Explanation:
Given
Wavelength of light 
Screen distance 
First fringe is at a distance 
No of lines per mm is given by N
where d=slit width
From N-slits Experiment
Position of bright fringe is given by
Put the value of 
in eq. 1
Therefore 
for 
The magnetic force on a moving charge, depends on three four things: the magnitude of the charge, the velocity of the charge, the strength of the magnetic field, and the angle between the velocity and the magnetic field.
