Answer:
The angle of incidence is
Explanation:
The diagram for this question is shown on the first uploaded image
From the question we are told that
The distance between the mirror and the wall is 
The height of the above the mirror is 
Generally the angle which the reflected ray make with the mirror is mathematically evaluated as

substituting values


From the diagram we can deduce that the angle of incidence is

So
electric potential energy..electrons get the the kinetic energy from the voltage applied across the conductor
X =(3.00x4.00 x3-1.00t x 2.00) x m
x= (12.00x3- 1.00 x2.00) x m
x= 36.00 -1.00 x 2.00) x m
x = (36.00 -2.00) x m
x =( 34.00) x m
x =34.00 times m