Different conformations of the same molecule are called

Which of the following is not a part of the stamen?

The potential energy for a force field $\vec{F}$ is given by $U(x, y) = \cos(x + y)$. The force acting on a particle at the position given by coordinates $(0, \pi/4)$ is:

Two discs of moments of inertia $I_1$ and $I_2$ about their respective axes (normal to the disc and passing through the centre),and rotating with angular speed $\omega_1$ and $\omega_2$ are brought into contact face to face with their axes of rotation coincident. What is the loss in kinetic energy of the system in the process?

Which of the following is not a polymer?

The wavelengths of light in two liquids '$x$' and '$y$' are $3500 \ \mathring A$ and $7000 \ \mathring A$ respectively. The critical angle of '$x$' with respect to '$y$' will be ...... $^o$.