B. evaporation
c. condensation
They are opposite processes that involve the same transfer of energy
Answer:
Therefore the surface area of the balloon is increased at 4 cm³/s.
Explanation:
The balloon is being filled with air at a rate of 10 cm³/s
It means the volume of the balloon is increased at a rate 10 cm³/s.
i.e 
Consider r be the radius of the balloon.
The volume of of a sphere is

Differentiate with respect to t



The surface of area of the balloon is(S) = 

Differentiate with respect to t


Putting the value of


Given that r = 5 cm
=4 cm³/s
Therefore the surface area of the balloon is increased at 4 cm³/s.
Answer:
k = 2.279
Explanation:
Given:
Magnitude of charge on each plate, Q = 172 μC
Now,
the capacitance, C of a capacitor is given as:
C = Q/V
where,
V is the potential difference
Thus, the capacitance due to the charge of 172 μC will be
C = 
Now, when the when the additional charge is accumulated
the capacitance (C') will be
C' = 
or
C' = 
now the dielectric constant (k) is given as:

substituting the values, we get

or
k = 2.279