Class 8 MCQs on Combustion and Flame,

1. In the presence of water, ignition Temperature of paper is-

a. Decrease                              b. Increase c. Remain constant                  d. None of these Ans.  (b)

2.The lowest temperature at which a Substance catches fire is called its-

a. Boiling point                                   b. Melting point c. Ignition temperature                        d. Critical temperature Ans.(c)

3.Which of the following is inflammable Substances?

a. Petrol                                   b. Wood c. Paper                                   d. Straw Ans.(a)

4.  Essential requirements for producing fire are:

a. Fuel                                     b. Air c. Heat                                     d. All of these Ans. (d)

5. Fire extinguisher-

a. Cut off the supply of air     b. Bring down the temperature of fuel c. Both (a) & (b)                      d. None of these Ans.(c)

6.  Rapid combustion is

a. When gas burns, it produces heat and light            b. When material suddenly burst into flames c. When there is evolution of heat                  d. None of these Ans.(a)

7. Explosion is the evolution of

a. Heat                                                             b. light c. Sound                                                          d. All of these Ans.(d)

8. Substance which vaporise during Burning gives

a. Sound                                                          b. Flame c. Combustion                                                 d. None of these Ans. (b)

9. Which is the hottest part in the flame of the candle

a. Blue                                                             b. Yellow c. Black                                                                       d. Wax part Ans. (a)

10. Innermost zone of candle flame  is the

a. Hottest part                                                 b. Moderately hot part c. Least hot part                                              d. Cold part Ans. (c)

11. Yellow colour in the cande  flame denotes

a. Outermost part                                            b. Middle zone c. Innermost zone                                            d. None of these Ans.(b)

12. Good fuel is

a. Readily available                                         b. Cheap c. Burn easily in air                                         d. All of these Ans.(d)

13. On burning fuel produces….. amount of heat

a. Large                                                           b. Less c. Very less                                                      d. No heat Ans.(a)

14. Use of ….. in vehicle reduces pollution

a. Petrol                                                           b. Diesel c. CNG                                                                        d. None of these Ans.(c)

15. Ideal fuel has ____ calorific value

a. Low                                                 b. High c. Moderate                             d. Zero Ans. (b)

16. Calorific value is measured in

a. Kilo joule                             b. Kilograms c. Kilo joule per Kg                 d. Kilometre Ans.(c)

17. Unburnt carbon particles causes

a. Stomach infections              b. Respiratory problems c. Brain infections                   d. Throat problems Ans.(b)

18. Incomplete combustion gives

a. CO2                                     b. CO c. Carbon                                 d. None of these Ans.(b)

19.  Goldsmith uses ____part of the flame for melting gold

a. Outermost                           b. Middle c. Innermost                            d. Both (b) & (c) Ans. (a)

20. Burning of coal and diesel releases

a. NO2                                                b. CO2 c. SO2                                     d. CO Ans.(c)

21. Petrol engine gives off gaseous oxides of

a. Sulphur                                b. Nitrogen c. Phosphorous                                    d. Carbon Ans.(b)

22. Acid rain is caused by oxides of

a. Sulphur, Nitrogen                b. Sulphur, Carbon c. Carbon, Nitrogen                d. Phosphorous, Carbon Ans.(a)

23. In the sun, heat and light are produced by

a. Chemical reactions              b.Nuclear reactions c.Ionic reactions                      d.None of these Ans.(b)

24. The head of the safety matchsticks contains

a. Antimony disulphide                      b Potassium Chlorate c. Both (a) and (b)                   d. None of these Ans.(c)

25. When the matchsticks  struck against rubbing surface, red phosphorous

a. Converts into white phosphorous   b. Reacts with potassium chlorate c. Ignite antimony disulphide             d. None of these Ans.(a)