The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?

Question: Which of the following radioactive wastes emits all α, β & γ rays and hence is the most hazardous of all radioactive emitters?
[A].

I-131

[B].

Sr-90

[C].

Au-198

[D].

Ra-226

Answer: Option D

Explanation:

No answer description available for this question.

Question: Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools).
[A].

1-2

[B].

5-10

[C].

15-20

[D].

25-30

Answer: Option B

Explanation:

No answer description available for this question.

Question: Fine grit present in sewage is removed in the __________ during sewage treatment.
[A].

grit chamber

[B].

detritus tank

[C].

trickling filter

[D].

skimming tank.

Answer: Option B

Explanation:

No answer description available for this question.