Combustion and Flame Test

Question 1
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Which of the following represents the correct increasing order of calorific value of the given fuels?

A
Hydrogen < LPG < Biogas < Cow dung cake < coal

B
Cow dung cake < Biogas < LPG < Coal < Hydrogen

C
Cow dung cake < Coal < Biogas < LPG < Hydrogen

D
Hydrogen < Cow dung cake < LPG < Biogas < Coal

Question 2
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Liquids and gaseous fuels have more advantages over solid fuels. Some of the advantages are

(i) Calorific value of liquid and gaseous fuels is higher than the solid fuels.

(ii) Liquids and gaseous fuels have higher ignition temperatures than the solid fuels.

(iii) Liquids and gaseous fuels are easier to store since solid fuels occupy lot of space.

(iv) Liquids and gaseous fuels burn completely, leaving no residue.

The correct advantages are

A
(i), (ii) and (iii)

B
(i), (iii) and (iv)

C
(ii), (iii) and (iv)

D
(i), (ii) and (iv).

Question 3
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Which of the following statements are true?

I. Yellow flames are ideal for heating.

II. The substances which vaporise during burning give flames.

III. Luminous zone contains unburnt carbon particles.

IV. The non-luminous zone has highest temperature.

A
I, II and III

B
I, II and IV

C
II, III and IV

D
I, III and IV

Question 4
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Calorific values of some fuels are given:

Fuel Calorific value (kJ/kg)

Coal 25000-33000

Diesel 45000

LPG 55000

CNG 50000

On the basis of this data, find out the correct order of efficiency of fuels.

A
LPG > CNG > Diesel > Coal

B
Coal > Diesel > LPG > CNG

C
Diesel > CNG > Coal > LPG

D
CNG > LPG > Diesel > Coal

Question 5
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Mark the correct statements) among the following.

I. Water is a very good fire extinguisher as it cools down the fuels such as wood below its ignition temperature.

II. Water is a very good fire extinguisher for burning oils and electrical equipment?

III. Sand and soil may act as a good fire extinguisher for burning oils.

A
I only

B
II only

C
III only

D
I and III only

Question 6
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Different methods of extinguishing a fire involve the following :

I. Removing the combustible substance.

II. Cooling the substance to a temperature below its ignition temperature.

III. Cutting off the supply of air.

Which of the following statements is correct?

A
Method I is suitable in case of a building on fire.

B
Method II involves water which works when wood or paper are on fire.

C
Method III involves carbon dioxide gas which is lighter than oxygen and forms a blanket around the air.

D
All of these

Question 7
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Directions For Questions

Natural resources are classified as:

P. Exhaustible

Q. Inexhaustible

Some natural resources are

(i) Petrol, diesel

(ii) Coal, petroleum

(iii) Air, water

(iv) Cow dung cakes, sunlight

(v) Forests, minerals

...view full instructions

Which of the following represents the correct match?

A

P-(iii), (iv); Q-(i), (ii), (v)

B

P-(i), (ii), (v); Q-(iii), (iv)

C

P-(ii), (v); Q-(i), (iii), (iv)

D
None of these is a correct match.

Submit Test

Combustion and ...

Question 1

Hydrogen < LPG < Biogas < Cow dung cake < coal

Cow dung cake < Biogas < LPG < Coal < Hydrogen

Cow dung cake < Coal < Biogas < LPG < Hydrogen

Hydrogen < Cow dung cake < LPG < Biogas < Coal

Question 2

(i), (ii) and (iii)

(i), (iii) and (iv)

(ii), (iii) and (iv)

(i), (ii) and (iv).

Question 3

I, II and III

I, II and IV

II, III and IV

I, III and IV

Question 4

LPG > CNG > Diesel > Coal

Coal > Diesel > LPG > CNG

Diesel > CNG > Coal > LPG

CNG > LPG > Diesel > Coal

Question 5

I only

II only

III only

I and III only

Question 6

Method I is suitable in case of a building on fire.

Method II involves water which works when wood or paper are on fire.

Method III involves carbon dioxide gas which is lighter than oxygen and forms a blanket around the air.

All of these

Question 7

P-(iii), (iv); Q-(i), (ii), (v)

P-(i), (ii), (v); Q-(iii), (iv)

P-(ii), (v); Q-(i), (iii), (iv)

None of these is a correct match.

User

Question Analysis

Fuel	Calorific value (kJ/kg)
Coal	25000-33000
Diesel	45000
LPG	55000
CNG	50000

Combustion and ...

Question 1

Hydrogen < LPG < Biogas < Cow dung cake < coal

Cow dung cake < Biogas < LPG < Coal < Hydrogen

Cow dung cake < Coal < Biogas < LPG < Hydrogen

Hydrogen < Cow dung cake < LPG < Biogas < Coal

Question 2

(i), (ii) and (iii)

(i), (iii) and (iv)

(ii), (iii) and (iv)

(i), (ii) and (iv).

Question 3

I, II and III

I, II and IV

II, III and IV

I, III and IV

Question 4

LPG > CNG > Diesel > Coal

Coal > Diesel > LPG > CNG

Diesel > CNG > Coal > LPG

CNG > LPG > Diesel > Coal

Question 5

I only

II only

III only

I and III only

Question 6

Method I is suitable in case of a building on fire.

Method II involves water which works when wood or paper are on fire.

Method III involves carbon dioxide gas which is lighter than oxygen and forms a blanket around the air.

All of these

Question 7

P-(iii), (iv); Q-(i), (ii), (v)

P-(i), (ii), (v); Q-(iii), (iv)

P-(ii), (v); Q-(i), (iii), (iv)

None of these is a correct match.

User

Question Analysis

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