By-products recovery process from coal carbonisation is termed as direct, indirect and semi direct process depending upon the method of recovery of

Which of the following statements is/are true? A: If a circle is formed from a wire, which was initially in the shape of a semi-circle, then ratio of radius of circle and that of semi-circle will be 7: 11. B: If in a semi-circle of radius ‘r’, another semi-circle of radius ‘4r/5’ is drawn, then area of the remaining part of larger semi-circle will be ‘3πr2/5’. C: In a circle of radius ‘r’, if ‘O’ is the center of circle and radii OA and OB are at the angle of 45°, then the length of major arc AB will be ‘7πr/8’.

A

Only A

B

Only B

C

Only C

D

None

Despite having large reserves of coal, why does India import millions of tonnes of coal? 1. It is the policy of India to save its own coal reserves for the future, and import them from other countries for the present use. 2. Most of the power plants in India are coal-based and they are not able to get sufficient supplies of coal from within the country. 3. Steel companies need a large quantity of coking coal which has to be imported. Which of the statements given above is/are correct?

A

1 only

B

2 and 3 only

C

1 and 3 only

D

1, 2 and 3

In India, what is the role of the Coal Controller's Organization (CCO)? 1. CCO is the major source of Coal Statistics in Government of India. 2. It monitors progress of development of Captive Coal/Lignite blocks. 3. It hears any objection to the Government's notification relating to acquisition of coal-bearing areas. 4. It ensures that coal mining companies deliver the coal to end users in the prescribed time. Select the correct answer using the code given below:

A

1, 2 and 3

B

3 and 4 only

C

1 and 2 only

D

1, 2 and 4

Historically, the production of wood charcoal in locations where there is an abundance of wood dates back to a very ancient period, and generally consists of piling billets of wood on their ends so as to form a conical pile, openings being left at the bottom to admit air, with a central shaft to serve as a flue. The whole pile is covered with turf or moistened clay. The firing is begun at the bottom of the flue, and gradually spreads outwards and upwards. The success of the operation depends upon the rate of the combustion. Under average conditions, 100 parts of wood yield about 60 parts by volume, or 25 parts by weight, of charcoal; small-scale production on the spot often yields only about 50%, while large-scale became efficient to about 90% even by the seventeenth century. The modern process of carbonizing wood, either in small pieces or as sawdust in cast iron retorts, is extensively practiced where wood is scarce, and also for the recovery of valuable byproducts (wood spirit, pyroligneous acid, wood tar), which the process permits. The information given, if accurate, most strongly supports which of the following?

A

The method which involves piling billets of wood on their ends, is the most efficient production process.

B

Modern processes of carbonizing wood, are the most efficient.

C

The rate of combustion is critical, to determine the amount and quality of coal produced

D

Large scale production of coal has become efficient due to the modern processes of producing coal.

Coke oven gas produced by high temperature carbonisation of coal (as compared to that produced by low temperature carbonisation), has

A

Higher calorific value

B

Lower hydrogen content

C

Both A & B

D

Neither A nor B

In high temperature carbonisation of coal compared to low temperature carbonisation

A

Yield of ammonia is less

B

Aromatic content of tar is low

C

H₂ content in the coke oven gas is more

D

Calorific value of the coke oven gas is lower

In high temperature carbonisation (as compared to low temperature carbonisation) of coal

A

Coke oven gas yield is more

B

Tar yield is less but free carbon in tar is more

C

Calorific value of coke oven gas is less

D

All of the above

In low temperature carbonisation (as compared to high temperature carbonisation) of coal

A

Ammonia yield is more

B

Aliphatic tar is produced

C

Free carbon in tar is more

D

All of the above

In low temperature carbonisation of coal as compared to high temperature carbonisation __________ produced is less.

A

Difference in gross & net calorific value of the coke oven gas

B

Free carbon content in tar

C

Yield percentage of coke

D

Yield of ammonia present in coke oven gas

In high temperature carbonisation (as compared to low temperature carbonisation) of coal, the

A

Gas yield is less

B

Tar yield is more

C

Ignition temperature of coke produced is less

D

Aromatic content of tar produced is more

By-products recovery process from coal carbonisation is termed as direct, indirect and semi direct process depending upon the method of recovery of

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