Advanced C&F+ S.F&P

A fuel 'Z' has CV of 71000kj/kg calculate the amount of fuel 'Z' required for the generation of 852MJ of energy

• 12g

• 12 kg

• 10,224g

• 10.224kg

Which of the following statements is NOT true?

• CO2 is the best fire extinguisher.

• Global warming can cause acid rain.

• Burning of coal and diesel releases sulphur dioxide gas.

• LPG has higher calorific value than biogas

When wood is used as fuel in chullahs, gaps are left in between the logs of wood. This is done for :

• (1) movement of air

• (2) less consumption of wood

• (3) to control temp

• (4) none of the above

For a spontaneous combustion to take place :

• (1) flame is required.

• (2) spark is required.

• (3) rise in temperature to ignition temperature is required.

• (4) nothing is required.

Which of the following statement is NOT true ?

• (1) Flame can be seen over burning solids and liquids.

• (2) Type of flame depends upon the amount of oxygen available.

• (3) Invisible zone of a flame is the least hot zone.

• (4) Blue zone indicates complete combustion of fuel.

When water is poured over burning wood, the fire goes off. This is because :

• (1) ignition temperature of wood decreases.

• (2) temperature of water goes up.

• (3) molecules of water reacts with oxygen present in the flame.

• (4) the flame vapourise.

If Raman opened the air hole of a bunsen burner fully and lighted the burner, he will get_________.

• (1) A luminous flame which is orange-yellow is colour.

• (2) A non-luminous flame which is pale blue in colour.

• (3) A flame that strikes back which is thin blue or green-yellow in colour.

• (4) A smoky flame which gives off a lot of soot.

Mr. Goyal. a science teacher showed the following experimental set up to the students. Which of the

following is the correct observation and its explanation?

• The paper pan catches fire and the water spills all over the wire mesh because paper is

  inflammable.

• The paper pan has a very high ignition temperature so it does not catch fire.

• The water in the pan absorbs heat from the candle flame and thus prevents the paper to reach

  the ignition temperature.

• The paper pan helps the water vapours to condense back to water.

Read the given statements carefully.

P : I am the most common fire extinguisher but not suitable for oil, petrol and electrical fires. I am

heavier than oil and also, conduct electricity.

Q : I am an excellent fire extinguisher and most suitable for oil, petrol and electrical fires. I also, form a

blanket around the fire and bring down the temperature of the fuel.

Identify P and Q.

• (1) P=CO₂ & Q= H₂O

• (2) P=H₂O & Q= CO

• (3) P=O₂ & Q= CO2

• (4) P=H₂O & Q= CO₂

Which of the following statements are true?

I. In the luminous zone of candle flame, vaporised wax gets oxidised to carbon dioxide which burns

with a blue flame.

II. There is no burning in the dark inner zone of the flame.

III. Non luminous zone is the hottest part of the flame.

IV. Luminous zone of a flame is mainly due to incomplete burning of carbon.

• (1) I and III only

• (2) II and III only

• (3) II, III and IV only

• (4) All of these