Discussion
Consider the following pairs of change and its effect on ground level concentration:
Higher wind speed - Lower concentration
Greater effective stack height - Lower maximum concentration
Shallower mixing height - Higher concentration
More unstable conditions - Higher concentration far downwind
How many of the pairs given above are correctly matched?
Answer: C
Correct answer: Only three
Three pairs are right. A higher wind speed lowers concentration, since \( u \) sits in the denominator; a greater effective stack height lowers the maximum, which varies roughly as \( 1/H^2 \); and a shallower mixing height raises concentration by reducing the volume available for dilution.
The fourth is wrong in its detail. More unstable conditions raise concentrations close to the stack, because the plume grows quickly and reaches the ground sooner, but they lower them far downwind, since the same vigorous mixing dilutes the plume rapidly thereafter. Instability moves the peak nearer and makes it higher, not the reverse.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development