SPECTROSCOPY

None of these

The diffraction grating

The entrance slit

The collimating lens

at anytime.

at no time.

when the amplitudes are the same.

when the frequencies match exactly

σ → σ*

n → π* and π → π*

n → σ*

none of these

a flashlight through a prism and shake it

a large mass on a weak spring

a class of spectroscopic techniques which analyzes molecular motions

an Infrared spectroscopy

All of these

Because, in liquids and solids, spectral lines corresponding to rotational transitions are broadened as the result of molecular collisions and other interactions

Because the energy required to induce a rotational transition is so small that it cannot be measured

Because rotational transitions are extremely rare