A. burning
B. adsorption
C. evaporation
D. absorption
Correct Answer:
Option B – adsorption
Explanation
The acetate and paper modify the particulate smoke phase by particle retention (filtration), and finely divided carbon modifies the gaseous phase (adsorption)

![Calculate the length of a constantan wire of cross-sectional area 4 π x 10-8m² and resistivity 1.1 x 10-6 Ω m required to construct a standard resistor of resistance 21 Ω. [Take π = 22/7] past-questions-and-answers](https://erudites.ng/wp-content/uploads/2020/06/past-questions-and-answers-150x150.jpg)