Is there any difference between beer Lambert's law and Lambert beer's law?

Answer 1

Beer's law says that absorbance of a molecule or solution is:
A = a*b*c
where A is the absorbance, "a" is the absorptivity (in units of per molar per cm, M-1 cm-1), "b" is the path length (in units of centimeters, cm), and "c" is the concentration (in units of molar, M). The absorptivity, is also commonly known as epsilon.
That means that the absorbance is linearly proportional to the thickness of the sample, the concentration of the absorbing medium, and the absorptivity, which is a measure of a given molecule's ability of absorb light.
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Answer 2

No, they refer to the same law, which describes the relationship between the concentration of a solution and the absorption of light by that solution. The name can be seen written both ways interchangeably.

Answer 3

Not at all, because both single Laws are multiplicative.