SPECTROSCOPY

The collimating lens

The diffraction grating

The entrance slit

None of these

when the frequencies match exactly

at anytime.

at no time.

when the amplitudes are the same.

none of these

σ → σ*

n → π* and π → π*

n → σ*

a class of spectroscopic techniques which analyzes molecular motions

a large mass on a weak spring

a flashlight through a prism and shake it

an Infrared spectroscopy

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

All of these

Because rotational transitions are extremely rare

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