Question

plz tell me the production theory which showed that energy and capital are perfectly substitutable or any theory name which discuss labor and energy but ignoring the capital in production model

Answer 1

Constant elasticity of substitution (CES), in economics, is a property of some production functions and utility functions.
As its name suggests, the CES production function exhibits constant elasticity of substitution between capital and labor. Leontief, linear and Cobb–Douglas functions are special cases of the CES production function.
Source:
https://en.m.wikipedia.org/wiki/Constant_elasticity_of_substitution