Scientists observe the world around them, from which to draw questions. Their predictions as to the answer are what we call a “hypothesis”. Thus, a scientist’s job is to answer the very hypotheses that they and their piers come up with.
Explanation:
The given data is as follows.
Energy needed for 1 mole = 279.7 kJ = 
= 279700 J
Therefore, energy required for 1 atom will be calculated as follows.

= 
As relation between energy and wavelength is as follows.
E = 
where, h = planck constant = 
c = speed of light = 
= wavelength
Therefore, putting given values into the above formula as follows.
E = 
=
=
or, =
m
= 428 nm
Thus, we can conclude that the maximum wavelength of light that can remove an electron from an atom on the surface of lithium metal is 428 nm.
Brass is an alloy, a substitutional alloy to be exact. Substitutional alloying is a type of alloying where certain metallic atom in a crystal structure is replaced with another constituents. Bronze is also a substitutional alloy. Bronze is made up of mostly copper with a mixture of zinc.