Which of the following could happen when infrared radiation is absorbed by a molecule ?
a) molecules begins to rotate more rapidly
b) molecule may glow in the dark
c) electrons are promoted from filled to empty molecular orbitals
d) the orientation of a nuclear spin state changes.
e) intramolecular bond angles change

       E) Intramolecular bond angles change

Explanation:

Infrared Radiation:

IR is electromagnetic radiations. The wavelength i.e. 700nm to 1000 mm of infrared is longer than invisible light and Its frequency is lower than light, that's why it is invisible to light.

So

The correct option is option E

       E) Intramolecular bond angles change

* Note:

it couldn't be option A as the frequency of IR is not enough to rotate a whole molecule

It Couldn't be option B as IR rations are electromagnetic radiation of longer wave length so it one can not see it with light so how it will glow a molecule

It also not could be the option C as for the excitation of electrons require much higher energy.

It also not the option D as nuclear magnetic spin is associated with nuclear magnetic radiation that are much different from IR.

50.23 i believe is correct but don't quote me on that.