With increase in the oxygen content of the coal, its __________ decreases.

Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.

A

1000

B

4000

C

6000

D

8000

Ash content in the middling coal (a byproduct of coal washeries) in India ranges between __________ percent.

A

15 to 25

B

35 to 45

C

55 to 75

D

75

Fusion point of coal ash increases with increase in its __________ content.

A

Iron sulphate

B

Iron silicate

C

Lime and magnesia

D

All of the above

The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by

A

TOD > BOD > COD

B

TOD > COD > BOD

C

BOD > COD > TOD

D

COD > BOD > TOD

With increase in moisture content of coal, its

A

Calorific value increases

B

Caking properties diminish

C

Swelling during carbonisation becomes excessive

D

None of these

Mineral matter content (M) and ash content (A) in coal are approximately related as

A

M = 1.1A

B

M = A

C

M = 1.5A

D

M = 2A

Proximate analysis of coal determines its __________ content.

A

moisture, ash, sulphur & volatile matter

B

moisture, volatile matter, ash & fixed carbon

C

moisture, sulphur, nitrogen & fixed carbon

D

none of the mentioned

The specific gravity of coal depends mainly on its __________ content.

A

Carbon

B

Volatile matter

C

Ash

D

Moisture

Ultimate analysis of coal determines its __________ content.

A

Carbon, hydrogen, nitrogen & sulphur

B

Carbon, ash, sulphur & nitrogen

C

Carbon, sulphur, volatile matter & ash

D

Carbon, volatile matter, ash & moisture

Coal is heated in presence of air to a temperature of about __________ °C, while determining its ash content for proximate analysis.

A

500

B

750

C

950

D

1100

With increase in the oxygen content of the coal, its __________ decreases.

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