Colorimetry and Spectrometry

Question 1

1. Spectroscopy deals with interaction of electromagnetic
   radiation with matter. What is the speed of this radiation
   in vacuum in m/s?
   a) 6 x 10^8
   b) 5 x 10^8
   c) 7 x 10^8
   d) 3 x 10^8

Answer 1

d) 3 x 10^8

Question 2

2. Which type of Quantum Transition takes place in Ultra
   Violet and Visible spectroscopy?
   a) Rotation of molecules
   b) Nuclear
   c) Bonding electrons
   d) Spin of nuclei in a magnetic field

Answer 2

c) Bonding electrons

Question 3

3. Which of the following is not a property or parameter of
   electromagnetic radiation?
   a) Wavelength
   b) Voltage
   c) Wave number
   d) Amplitude

Answer 3

b) Voltage

Question 4

5. Electromagnetic radiation can travel through a vacuum.
   a) True
   b) False

Answer 4

a) True

Question 4

4. Which of the following is not a type of Spectroscopy?
   a) Gamma ray
   b) X ray
   c) Nuclear magnetic resonance
   d) Sound

Answer 4

d) Sound

Question 5

6. Which of the following is false about the wavelengths of
   electromagnetic radiation?
   a) Radiation with short wavelengths have high energies
   b) Energy does not depend on wavelength
   c) Radiation with long wavelengths have low energies
   d) Energy depends on wavelength

Answer 5

b) Energy does not depend on wavelength

Question 6

7. Which of the following is the wavelength of microwave
   radiation?
   a) 10 – 780nm
   b) 0.78 – 30µm
   c) 0.6 – 10 m
   d) 0.75 – 3.75 mm

Answer 6

d) 0.75 – 3.75 mm

Question 7

9. Which of the following is the wavenumber of UV and
   Visible radiation?
   a) 1 x 106 to 1.3 x 10^4 m^-1
   b) 1 x 106 to 1.3 x 10^4 m
   c) 13 – 27 m^-1
   d) 1 x 106 to 1.3 x 10^4 m^2

Answer 7

a) 1 x 106 to 1.3 x 10^4 m^-1

Question 7

8. How is the wave number of electromagnetic radiation
   related to wavelength?
   a) It is the reciprocal of wavelength
   b) It is directly proportional to wavelength
   c) It is not related to wavelength
   d) It is equal to wavelength

Answer 7

a) It is the reciprocal of wavelength

Question 8

10. Velocity of electromagnetic radiation is more in a
    vacuum than in any medium.
    a) True
    b) False

Answer 8

a) True

Question 9

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 9

c) Energy absorption and concentration

Question 10

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 10

b) Radiation must have higher bandwidth

Question 11

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

Answer 11

a) Concentration

Question 12

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

Answer 12

b) Distance

Question 13

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 13

c) Absorptivity

Question 14

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 14

c) Reflection is kept maximum

Question 15

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 15

a) Radiant power transmitted by the sample

Question 16

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 16

d) No unit

Question 17

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 17

a) L mol^-1 cm^-1

Question 18

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 18

c) Absorption is the negative logarithm of transmittance