Explanation:
It is given that,
Magnetic field, B = 0.1 T
Acceleration, 
Charge on electron,
Mass of electron,
(a) The force acting on the electron when it is accelerated is, F = ma
The force acting on the electron when it is in magnetic field, 
Here, 
So, 
Where
v is the velocity of the electron
B is the magnetic field


v = 341250 m/s
or

So, the speed of the electron is 
(b) In 1 ns, the speed of the electron remains the same as the force is perpendicular to the cross product of velocity and the magnetic field.
Answer: The correct answer is "the pitch drops to a lower pitch once the ambulance passes by Juan".
Explanation:
Doppler effect is the phenomenon in which there is an increase or decrease in the frequency when there is relative motion between the source and listener.
Pitch depends on the frequency. if the frequency increases then pitch increases.
When the source and the listener are moving towards each other then there is increase in the frequency. When the source and the listener are moving away each other then there is decrease in the frequency.
In the given problem, Juan is standing on the street. An ambulance moves toward him and then passes by the pitch drops to a lower pitch once the ambulance passes by Juan.
If you read the question carefully, you can find the answer right there in it.
In fact, you don't even have to read the whole question ... you only need to read one word.
In fact, you don't even have to read the whole word ... you only need to read part of the word.
The word to read is "wavelength".
The important part of the word is "length".
<em>Now</em> it's time to look at the picture:
#1 is a height.
#2 is a place on the wave
#4 is a place on the wave
<em>#3 </em>is the only thing in the picture that's a "length" of anything.
The pressure in the balloon increases.