Question

Which of the following option is not suitable for environmental conditions in labs?

(a) Wet dust particles decrease insulation resistance

(b) Dry dust increase surface resistivity

(c) A negative air pressure should be maintained in labs

(d) Electrostatic precipitators used to collect dust particles

This question was addressed to me in final exam.

The doubt is from Conditions of Comparison topic in portion Standards of Measurements of Engineering Metrology

Answer 1

Right option is (c) A negative air pressure should be maintained in labs

To explain I would say: A positive air pressure of about 10 to 20 N/m^2 relative to outside area is recommended in labs. Electrostatic precipitators are used to collect and attract dust particles, for this purpose they can be placed in corners.