Question

6.What is the permissible noise limit of 120 db?
a) 30 minutes
b) 2 minutes
c) 1 minute
d) 30 seconds

7.Greenhouses gases causing a rise of 3℃ rise in the overall global temperature in the past century are CFCs. The CFC used in refrigerators is
a) Ammonia
b) Freon
c) Methane
d) Carbon dioxide

8.In which layer of atmosphere ozone is very vital for all vegetation?
a) Upper atmosphere
b) Below atmosphere
c) Ground level
d) Below ground level

9.Ozone can be destroyed by the following free radical(s)
a) Chlorine radical (Cl)
b) Hydroxyl radicals (OH)
c) Nitric oxide radical (NO)
d) all of these

10.Which of the following is the oldest and the most common method used to dump the solid wastes?
a) River
b) Ocean
c) Landfill
d) None of the above

11.Why is recycled paper banned for use in food containers?
a) Because it creates a lot of spaces
b) Because it creates contamination
c) Because paper can be used only one time
d) Because paper is very thick and can’t cover the food containers

12.What is called for a temporary hearing loss?
a) Temporary ear pain
b) Temporary hearing problem
c) Temporary threshold shift
d) Temporary hearing shift

13.Which of the following sound is pleasant to our ears?
a) Heavy machinery
b) Transportation equipment
c) Loud noise
d) Music

14.What is the dB of a threshold of hearing?
a) 0
b) 10
c) 50
d) 100​

Answer 1

Answer:

Match the following elements of column I with their prop

Column 1

Column II

1. Chlorine

(a) Solid

halogen

2. Fluorine

(b) Radioactive

3. Bromine

(c) Reddish brown liquid

4. Iodine

(d) Highest electron affinity

5. Astatine

(e) Most electronegative

Complete the following equations :

Na