Physics, asked by JacobIsrael, 3 months ago

17)Combustion of a substance releases heat and ___.

a) oxygen

b) wood

c) light

d) water

18) The suspended particles released by combustion of coal in air may lead to a health disease.

Select the correct option.

a) Goitre

b) Arthritis

c) Asthma

d) Bone cancer

19 What is the main chemical component present in striking surface of a matchbox?

a) Potassium chlorate

b) Phosphorus

c) Potassium

d) Graphite

20) When a cracker is ignited, a sudden reaction takes place with the evolution of heat, light

and sound. Identify the type of combustion?

a) Random combustion

b) Rapid combustion

c) Spontaneous combustion

d) Explosion

21 The SI unit of the calorific value of a fuel is :-

a) N/kg

b) KJ/kg

c) KW/kg

d) J/kg

22 Which of the following factors are essential to ignite a fire?

a) All of these

b) Fuel

c) Air (oxygen)

d) Heat

23) Water cannot be used as a fire extinguisher to put out –

a) Burning charcoal b) Burning cloth

c) Burning oil

d) Burning wood

24 Fuel may bea) Solid

b) Liquid

c) Gas

d) All of these

25 The lowest temperature at which a Substance catches fire is called itsa) Boiling point

b) Melting point

c) Ignition temperature

d) Critical temperature

26 Fire extinguishera) Cut off the supply of air

b) Bring down the temperature of fuel

c) Both (a) & (b)

d) None of these

27.Unburnt carbon particles causes

a) Stomach infections

b) Respiratory problems

c)Brain infections

d) Throat problems

28 .Which of the following is/are carbon fuel

a) Wood

b) Coal

c) Petroleum

d) All of these

29 Acid rain is caused by oxides of

a) Sulphur, Nitrogen

b) Sulphur, Carbon

c) Carbon, Nitrogen

d) Phosphorous, Carbon​

Answers

Answered by Anonymous
4

Your answers:-

17. a) Oxygen

18. c) Asthma

19. b) Phosphorus

20. d) Explosion

21. b) kJ/kg

22. a) All of these

23. c) Burning Oil

24. d) All of these

25. c) Ignition temperature

26. c) Both a and b

27. b) Respiratory diseases

28. b) Coal

29. a) Sulphur, nitrogen.

Answered by Anonymous
4

Answer:

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19.Light

20.asthma

21.phosphorus

22.rapid combustion

23.kJ/kg

24.all of these

25.Ignition temperature

26. Both a and b

27.throat problem

28.coal

29.Sulphur, Nitrogen

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