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Beer-Lambert Law Questions

The attenuation of light to the material’s properties through which the light travels is given by the Beer-Lambert law. This law is also known as Lambert-Beer law, Beer-Lambert–Bouguer law or Beer’s law. Beer-Lambert law is a combination of Beer’s law and Lambert’s law.

It states that, for a given material, the sample path length and concentration of the sample are directly proportional to the absorbance of the light.

It is given by the formula: A = εLc

Where,

c – Concentration of the absorbing species

A – Quantity of light absorbed for a particular wavelength by the sample

L – Distance covered by the light through the solution

ε – Molar extinction coefficient

Beer Lambert law is given by the expression

\(\begin{array}{l}\large I=I_{0}e^{-\mu (x)}\end{array} \)
.

Where,

I – intensity

\(\begin{array}{l}I<sub>0</sub>\end{array} \)
– initial intensity

μ – coefficient of absorption

x – depth in meter

Read more: Beer-Lambert Law

Important Beer-Lambert Law Questions with Answers

1. The sample path length and concentration of the sample are directly proportional to the _____.

  1. Reflection of light
  2. Refraction of light
  3. Absorbance of the light
  4. Intensity of the light

Answer: c) Absorbance of the light

Explanation: As per the Beer-Lambert law, for a given material, the sample path length and concentration of the sample are directly proportional to the absorbance of the light.

2. Who stated Beer’s law?

Beer’s law was stated by August Beer.

3. Who discovered the Beer-Lambert law?

  1. August Beer
  2. Michel Faraday
  3. Johann Heinrich Lambert
  4. Pierre Bouguer

Answer: d) Pierre Bouguer

Explanation: The Beer-Lambert law was basically discovered by Pierre Bouguer.

4. The coefficient of absorption is represented by _____.

  1. \(\begin{array}{l}\alpha \end{array} \)
  2. \(\begin{array}{l}\mu \end{array} \)
  3. \(\begin{array}{l}\beta \end{array} \)
  4. \(\begin{array}{l}\epsilon \end{array} \)

Answer: b)

\(\begin{array}{l}\mu \end{array} \)

Explanation: The coefficient of absorption is represented by the symbol

\(\begin{array}{l}\mu \end{array} \)
.

5. State true or false: Stellar radiation is described using the Beer-Lambert law.

  1. TRUE
  2. FALSE

Answer: a) TRUE

Explanation: Stellar radiation or Solar radiation can be described using the Beer-Lambert law.

6. Attenuation is the rate at which the signal light _______in intensity.

  1. Decreases
  2. Increases

Answer: a) Decreases

Explanation: light intensity is reduced when it undergoes attenuation.

7. The bilirubin count in the blood can be found using which device?

Bilirubin in the blood can be determined using the spectrophotometer.

8. Can Beer-Lambert law be used to study the absorptivity coefficient of higher concentration samples?

  1. YES
  2. NO

Answer: b) NO

Explanation: It cannot be used since the Beer-Lambert law fails at higher concentrations.

9. How is Beer-Lambert law used in the field of chemistry?

The Beer-Lambert law is used to find the concentration of chemical solutions.

10. State true or false: When the concentration is high, the refractive index changes.

  1. TRUE
  2. FALSE

Answer: a) TRUE

Explanation: Yes, the refractive index changes when the concentration is high.

Practice Questions

  1. Define the attenuation of light.
  2. State Beer-Lambert law.
  3. What is the formula of Beer-Lambert law?
  4. Is the Beer-Lambert law used when fluorescent compounds are used?
  5. What is a spectrophotometer?
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