UV Visible Spectrometers

Question 1

Beer Lambert’s law gives the relation between which of the following?
a) Reflected radiation and concentration
b) Scattered radiation and concentration
c) Energy absorption and concentration
d) Energy absorption and reflected radiation

Answer 1

c) Energy absorption and concentration

Question 2

In which of the following ways, absorption is related to transmittance?
a) Absorption is the logarithm of transmittance
b) Absorption is the reciprocal of transmittance
c) Absorption is the negative logarithm of transmittance
d) Absorption is a multiple of transmittance

Answer 2

c) Absorption is the negative logarithm of transmittance

Question 3

Which of the following is not a limitation of Beer Lambert’s law, which gives the relation between absorption, thickness and concentration?
a) Concentration must be lower
b) Radiation must have higher bandwidth
c) Radiation source must be monochromatic
d) Does not consider factors other than thickness and concentration that affect absorbance

Answer 3

b) Radiation must have higher bandwidth

Question 4

Beer’s law states that the intensity of light decreases with respect to ___________
a) Concentration
b) Distance
c) Composition
d) Volume

Answer 4

a) Concentration

Question 5

Lambert’s law states that the intensity of light decreases with respect to __________
a) Concentration
b) Distance
c) Composition
d) Volume

Answer 5

b) Distance

Question 6

The representation of Beer Lambert’s law is given as A = abc. If ‘b’ represents distance, ‘c’ represents concentration and ‘A’ represents absorption, what does ‘a’ represent?
a) Intensity
b) Transmittance
c) Absorptivity
d) Admittance

Answer 6

c) Absorptivity

Question 7

Which of the following is not true about Absorption spectroscopy?
a) It involves transmission
b) Scattering is kept minimum
c) Reflection is kept maximum
d) Intensity of radiation leaving the substance is an indication of a concentration

Answer 7

c) Reflection is kept maximum

Question 8

Transmittance is given as T = P/Po. If Po is the power incident on the sample, what does P represent?
a) Radiant power transmitted by the sample
b) Radiant power absorbed by the sample
c) Sum of powers absorbed and scattered
d) Sum of powers transmitted and reflected

Answer 8

a) Radiant power transmitted by the sample

Question 9

What is the unit of absorbance which can be derived from Beer Lambert’s law?
a) L mol-1 cm-1
b) L gm-1 cm-1
c) Cm
d) No unit

Answer 9

d) No unit

Question 10

What is the unit of molar absorptivity or absorptivity which is used to determine absorbance A in Beer Lambert’s formula?
a) L mol-1 cm-1
b) L gm-1 cm-1
c) Cm
d) No unit

Answer 10

a) L mol-1 cm-1