Spectroscopy

Question: Why are rotational transitions of little use to a spectroscopist?
[A].

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

[B].

Because rotational transitions are extremely rare

[C].

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

[D].

All of the above

Answer: Option C

Explanation:

No answer description available for this question.

Question: Why must the voltage supplied to a tungsten lamp be very stable?
[A].

Because if it wasn’t, the lamp would bum out

[B].

Because amount of energy the lamp emits is proportional to the fourth power of the operating voltage

[C].

Because the lamp will only function at a specific voltage

[D].

All of the above

Answer: Option B

Explanation:

No answer description available for this question.

Question: Molar absorbtivities of compounds exhibiting charge transfer absorption are
[A].

small

[B].

moderate

[C].

large

[D].

none of these

Answer: Option C

Explanation:

No answer description available for this question.

Question: Beer’s Law states that
[A].

absorbance is proportional to both the path length and concentration of the absorbing species

[B].

absorbance is proportional to the log of the concentration of the absorbing species

[C].

absorbance is equal to P0 / P

[D].

none of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: Molar absorbtivity is the measure of the
[A].

amount of light absorbed per unit length

[B].

amount of light absorbed per unit concentration

[C].

amount of light reflected and absorbed per unit concentration

[D].

None of the above

Answer: Option B

Explanation:

No answer description available for this question.

Question: Why is it generally preferable to use absorbance as a measure of absorption rather than % transmittance?
[A].

Because %T cannot be measured as accurately as absorbance

[B].

Because %T is dependant on the power of the incident radiation

[C].

Because absorbance is proportional to the concentration of the analyte, whereas %T is not

[D].

none of the above

Answer: Option C

Explanation:

No answer description available for this question.

Question: In the equation, A = ε bc, what quantity is represented by “ε”?
[A].

Absorbtivity

[B].

Molar absorbtivity

[C].

Path length

[D].

None of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Which of the following relationships between absorbance and %transmittance is incorrect?
[A].

A = log10 100 / %T

[B].

A = 2 – log10 %T

[C].

A = log10 1 / T

[D].

All are correct

Answer: Option C

Explanation:

No answer description available for this question.

Question: In the past, IR spectra had to be aquired one wavelength at a time, which took a long time. Today quick spectra is due to the
[A].

the Fourier Transfer Algorithm allows us to scan all frequencies at once

[B].

light is faster today that it used to be

[C].

absence of broad spectrum of wavelenth

[D].

none of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: A simple harmonic oscillator may absorb energy
[A].

at anytime.

[B].

when the frequencies match exactly

[C].

when the amplitudes are the same.

[D].

at no time.

Answer: Option B

Explanation:

No answer description available for this question.