Answer:
B 4.18J\g degree C is the specific heat of water
Explanation:
It is given that,
Kinetic energy of the electron, 
Let the east direction is +x direction, north direction is +y direction and vertical direction is +z direction.
The magnetic field in north direction, 
The magnetic field in west direction, 
The magnetic field in vertical direction, 
Magnetic field, 
Firstly calculating the velocity of the electron using the kinetic energy formulas as :



(as it is moving from west to east)
The force acting on the charged particle in the magnetic field is given by :


Since, 
And, 
![F=1.6\times 10^{-19}\times [1178 k-2864.20j]](https://tex.z-dn.net/?f=F%3D1.6%5Ctimes%2010%5E%7B-19%7D%5Ctimes%20%5B1178%20k-2864.20j%5D)


(b) Let a is the acceleration of the electron. It can be calculated as :



Hence, this is the required solution.
This problem must be solved using a sketch. I attached an illustration of the problem.
You must trace the ray that reflects from the top off the table to your eyes. This how eyesight works, light rays reflects off the objects into your eyes.
Law of reflection tells us that light ray reflects off the surface at the same angle in which it falls on it( i attached another illustration of this).
Now we can write tangens equations:

We solve for h: