Explanation:
The relationship between the wavelength and the potential difference V is given by :

Putting the values of known parameters,

(a) 


(b) 


Hence, this is the required solution.
Very high melting<span> points - Substances with giant covalent structures have very high</span>melting<span> points, because a lot of strong covalent bonds must be broken. Graphite, for example, has a </span>melting point<span> of more than 3,600ºC. Variable conductivity - Diamond does not conduct electricity.</span>
Check Google it might have the answer sorry I couldn't be much help
In this case, you need the formula below where:
F = force
k = coulombs constant 8.99 x10^{9} N.m^{2} . C^{-2}
q1 = electric charge 1
q2 = electric charge 2
r = the distance between the charges

pls note: make sure your units are correct (in meters etc, not fm (<em>femto-meters</em>)).
Curiously, this question doesn't tell you what atom you are next to the nucleus of. Different numbers of protons in the nucleus of the atom will make for vastly different forces in your answer...
On half life is 5370 years; 6 half lives have passed. You just multiply,
5370*6 = 32,220 years