I tested creep in the labs at univeristy, one thing i am confused about is, we made a graph of the extension against time. Taking the gradient gives us E or secondary creep rate. 1. The problem statement, all variables and given/known data The equation for this (without using gradient ) is, E= A stress^n e^-Qc/RT A and n are constants ( i know n is the stress exponent which for the material (lead) was 10) Qc is the activation energy, can't find anything about this. R is universal gas constant 8.31 J/mol K Note: the test was done at room temperature. T is absolute temp. Really confused by this, the experiment helper didn't explain any of this.