11.In sun heat and light are produced by …………………
(A) Nuclear reactions
(B) Nuclear fusion
(C) Nuclear heat
(D) Nuclear Light
12.The lowest temperature at which a substance catches fire is called its
(A) Ignition temperature
(B) Spontaneous temperature
(C) Autoignition temperature
(D) None of the above
13.…………..is used to wrap around a person whose clothes caught fire.
(A) Synthetic cloth
(B) Plastic
(C) Blanket
(D) None of the above
14.The striking surface of the matchbox contains ……
(A) Powdered glass and little red phosphorous
(B) White and red phosphorous
(C) Powdered glass and antimony trisulphide
(D) None of the above
15.The head of the matchstick contains ……….
(A) White phosphorous and trisulphide
(B) Antimony trisulphide and potassium chlorate
(C) Powdered glass and little white phosphorous
(D) None of the above
16.What will happen when the match is struck against the rubbing surface?
(A) white phosphorous gets converted into red phosphorous and immediately reacts with potassium chlorate in matchstick head to produce enough heat to ignite antimony trisulphide and start the combustion
(B) Red phosphorous gets converted into white phosphorous and immediately reacts with potassium chlorate in matchstick head to produce enough heat to ignite red sulphate and start the combustion
(C) Red phosphorous gets converted into white phosphorous and immediately reacts with potassium chlorate in matchstick head to produce enough heat to ignite antimony trisulphide and start the combustion
(D) None of the above
17.The substances which have very low ignition temperature and can easily catch fire with a flame are called ……………..
(A) Inflammable substances
(B) Combustible substances
(C) Flammable substances
(D) None of the above
18.Which of the following is an example of inflammable substances?
(A) LPG
(B) Alcohol
(C) Petrol
(D) All of the above
19.What a fire brigade pours on the fire to reduce the ignition temperature low?
(A) Oil
(B) Water vapours
(C) Silt
(D) All of the above
20.Fire can be controlled by removing …………….
(A) Fuel
(B) Air
(C) Heat
(D) One or more from fuel, air and heat
Answers:-
| 11-(B) | 12-(A) | 13-(C) | 14-(A) | 15-(B) | 16-(C) | 17-(A) | 18-(D) | 19-(B) | 20-(D) |