Answer:
The magnitude of electron acceleration is

Explanation:
Given:
Distance from the wire to the field point
m
Speed of electron 
Current
A
For finding the acceleration,
First find the magnetic field due to wire,

Where 

T
The magnetic force exerted on the electron passing through straight wire,

N
From the newton's second law

Where
mass of electron
kg
So acceleration is given by,



Therefore, the magnitude of electron acceleration is

The correct option is B.
The length of an object, the mass of an object and the rate of time passage for an object can change depending on the situation which the object is subject to. For instance in space, the mass and the velocity of an object usually change. But, the value of the speed of light in the space is the same for all observers regardless of the motion of an object, that is, the speed of light is a constant.<span />
energy is the correct answer to fill the blank bb :)
Explanation:
Period P has units of seconds (s).
Length has units of meters (m).
Mass has units of kilograms (kg).
Acceleration has units of meters per second squared (m/s²).
Dimensional analysis:
s = √(m / (m/s²))
Therefore:
P = k √(L/g)
where k is a dimensionless constant.