List of top Polymer Science and Engineering Questions on Visco-elasticity- creep and stress relaxations asked in GATE XE

During material testing, stress is applied from time \(t_i\) to \(t_f\).
The corresponding strain responses for three different materials are shown in plots P, Q, and R.
Choose the option(s) where the strain response is correctly mapped to its material class.
Among the options given, identify the correct pair(s) of catalyst and co-catalyst that form a Ziegler–Natta catalyst.
The behavior of a polymer is described by a Maxwell model consisting of a spring element of modulus \( 10^{10} \) Pa in series with a dashpot of viscosity \( 10^{12} \) Pa.s. In the solid, 50 s after the sudden application of a fixed strain of 1%, the stress (rounded off to 2 decimal places) will be \(\underline{\hspace{2cm}}\) \( \times 10^7 \) Pa.