Objects in contact with each other never get past the electron clouds of the atoms on their surfaces.
Number 19 is frequency and not sure which question you asked!!!??
Answer:
The time constant is 
Explanation:
From the question we are told that
the time take to charge is 
The mathematically representation for voltage potential of a capacitor at different time is

Where
is the time constant
is the potential of the capacitor when it is full
So the capacitor potential will be 100% when it is full thus
100% = 1
and from the question we are told that the at the given time the potential of the capacitor is 85% = 0.85 of its final potential so
V = 0.85
Hence



Answer:
Increasing its charge
Increasing the field strength
Explanation:
For a charged particle moving in a circular path in a uniform magnetic field, the centripetal force is provided by the magnetic force, so we can write:

where
q is the charge
v is the velocity
B is the magnetic field
m is the mass
r is the radius of the orbit
The period of the motion is

Re-arranging for r

And substituting into the previous equation

Solving for T,

So we see that the period is:
- proportional to the charge and the magnetic field
- inversely proportional to the mass and the square of the speed
So the following will increase the period of the particle's motion:
Increasing its charge
Increasing the field strength