what is difference between deteminate and indeterminate beam?

Determinate structures :
These Structures are analysed just by the use of basic equilibrium equations. By this analysis, the unknown reactions are found for the further determination of stresses.
E.g: simply supported beams, cantilever beams, single and double overhanging beams, three hinged arches, etc


Redundant or indeterminate structures :
These Structures are not capable of being analysed by mere use of basic equilibrium equations. Along with the basic equilibrium equations, some extra conditions are required to be used like compatibility conditions of deformations etc to get the unknown reactions for drawing bending moment and shear force diagrams
E.g: fixed beams, continuous beams, fixed arches, two hinged arches, portals, multistoried frames, etc.