Your answer is- amplitudes
Explanation:
The charge on the electron is, 
The electric field at a distance r from the electron is :

Where
k is the electrostatic constant, 
We know that the electric field lines starts from positive charge and ends at the negative charge. Also, for a positive charge the field lines are outwards while for a negative charge the field lines are inwards.
So, the correct option is " the electric field is directed toward the electron and has a magnitude of
. Hence, this is the required solution.
Explanation:
It is given that,
Frequency of diagnostic ultrasound, f = 3.82 MHz = 3820 Hz
The speed of the sound in air, v = 343 m/s
(a) We need to find the wavelength in air of such a sound wave. Let it is given by λ₁
i.e. 


(b) If the speed of sound in tissue is 1650 m/s .



Hence, this is the required solution.
Hi,
My best answer would be Gravity. Is it a multiple choice question? Or is it an essay question.
I think your best bet would be.
It acts in the direction opposite of the motion