In infrared gas analyser, the amount of absorption is the function of

Question

 Assertion (A): In infrared gas analyser, the amount of absorption is the function of concentration of the gas and the length of the absorption path.

Reason (R): Different gases are characteristic by distinctive absorption bands within the infrared range.

1. Both A and R are individually true and R is the correct explanation of A
2. Both A and R are individually true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true