just search up the answer/ definition to all of them, rephrase into own words, then do the same for examples.
Answer:
(a) 5.04 eV (B) 248.14 nm (c) 
Explanation:
We have given Wavelength of the light \lambda = 240 nm
According to plank's rule ,energy of light


Maximum KE of emitted electron i= 0.17 eV
Part( A) Using Einstien's equation
, here
is work function.
= 5.21 eV-0.17 eV = 5.04 eV
Part( B) We have to find cutoff wavelength



Part (C) In this part we have to find the cutoff frequency

Answer:
The electric force between them is 878.9 N
Explanation:
Given:
Identical charge
C
Separation between two charges
m
For finding the electrical force,
According to the coulomb's law

Here, force between two balloons are repulsive because both charges are same.
Where 

N
Therefore, the electric force between them is 878.9 N