Question 1 :
The lowest temperature at which a substance catches fire is called its __________ temperature.
Question 2 :
Manu was heating oil to fry potato chips. The cooking oil all of a sudden caught fire; he poured water to extinguish the fire. Why was the action of Manu not suitable.
Question 3 :
The portion of the flame just outside gets red hot on burning. What type of area it is?
Question 4 :
Explosion can also take place if____ is applied on the cracker.
Question 6 :
State true or false. Carbon dioxide is an excellent fire extinguisher.
Question 10 :
Two glass jars A and B are filled with carbon dioxide and oxygen gases, respectively. In each jar a lighted candle is placed simultaneously. In which jar will the candle remain lighted for a longer time?
Question 11 :
True or False. A good fuel is one which is not readily available.
Question 12 :
Is it True or false that middle zone is the hottest zone of a flame?
Question 13 :
The use of diesel and petrol as fuels in automobiles is being replaced by______ gas
Question 18 :
The calorific value of a fuel is expressed in a unit called
Question 19 :
Fill in the blank: A liquid fuel used in homes is __________.
Question 21 :
Manu was heating oil to fry potato chips. The cooking oil all of a sudden caught fire; he poured water to extinguish the fire. Do you think this action was suitable?
Question 22 :
True or False. $CO_2$ not only forms a blanket around the fire, it also brings down the temperature of the fuel.
Question 23 :
Is it True or False that water is the best extinguisher for fires involving electrical equipment?
Question 26 :
Which of the following is/are an example(s) of a solid fuel.
Question 29 :
The calorific values of petrol and CNG are 45000 kJ/kg and 50,000 kJ/kg, respectively. If you have vehicle which can run on petrol as well as CNG, which fuel will you prefer, why?
Question 31 :
Fill in the blank: Fire produced by oil cannot be controlled by _________.
Question 33 :
State TRUE or FALSE: It is difficult to burn a heap of green leaves but dry leaves catch fire easily.
Question 34 :
Fill in the blank: Burning of wood and coal causes __________ of air.
Question 35 :
State TRUE or FALSE: The head of the safety match contains only Antimony Trisulphide, Potassium Chlorate and White Phosphorus with some glue.
Question 36 :
Is it essential for a substance to reach ignition temperature to burn?
Question 37 :
Does kerosene oil or molten wax vapourise and produce a flame?
Question 40 :
Choose the incorrect statement from the following. A good fuel is one which:
Question 42 :
The substances which have very ________________ ignition temperature and can easily catch fire with a flame are called __________ substances.
Question 43 :
Wood do not catch fire on their own at room temperature. But if wood is heated a little, would it still catch fire?
Question 49 :
Gas burns rapidly and produces heat and light. Such combustion is known as-
Question 50 :
Is it True or false that Alcohol, CNG and LPG are inflammable substances?