Answer with Explanation:
It is given that
1) Force of Drag 
2) Weight 
Equating drag and weight we get

where,
'm' is mass of the object
'g' is acceleration due to gravity
'A' is the area of the person
is the density of air
Approximating the weight of a man to be 75 kg and area of man 
Applying the values in the formula we get


Answer:
595391.482946 m/s

Explanation:
E = Energy = 1.85 keV
I = Current = 5.15 mA
e = Charge of electron = 
t = Time taken = 1 second
m = Mass of proton = 
Velocity of proton is given by

The speed of the proton is 595391.482946 m/s
Current is given by

Number of protons is

The number of protons is 
Answer:
a) If I increase the number of moving charged particles per cubic meter in a conductor, I will have to increase the cross sectional area of the conductor to get the same amount of current for the same electric field in the conductor.
FALSE
As we know that

so here if we increase the number of charge per unit volume then we need to decrease the area to get same amount of current through the wire.
b) The change in magnetic flux in a closed loop induces an EMF that opposes the change in magnetic flux.
TRUE
As per lenz law the direction of induced EMF is always opposite to the change in the flux due to which EMF is induced in the closed loop.
c) The magnetic force per unit length of two long, parallel, current-carrying conductors is repulsive if the currents are flowing in the opposite direction.
TRUE
When magnetic field of first wire will interact with other then it will exert force on it
so here the force will be on other wire such that the two wire will repel when current in the two wires is opposite in direction.
d) . The total magnetic flux through a closed surface is equal to μ0I enclosed
FALSE
magnetic flux is the number of field lines passing through a given area
So it is given as
