The Questions are based on NCERT Syllabus 

Topics Covered : 

  1. Chemical effects of Electric Current
  2. Combustion of Flame 

                   

     SCIENCE TEST – I    For Class 8th F.M.:- 50

Q1. Each question carries 1mark.

(i) Name some materials which are good conductors of electricity.

(ii) The path through which an electric current flows is called

  1. Electric path b. Electric relay              c. Short circuit               d. Electric circuit

(iii) How chlorination is done to purify water?

(iv) Fuel must be heated to its_________________ before it starts burning.

(v) Name the gases involved in acid rain.

Q2. Each question carries 2marks.

(i) In an experiment 3.5 kg of a fuel was completely burnt. The heat produced was measures to be 160,000 kj. Calculate the calorific value of the fuel.

(ii) Explain why it is difficult to burn a heap of green leaves but we can easily burn dry leaves?

(iii) What do you mean by marble cancer?

(iv) How smog is harmful to us?

(v) It is said that rain water is as pure as distilled water, but once while testing rain water compass needle shows deflection, explain why?

Q3. Each question carries 3marks.

(i) Write short notes on greenhouse gases.

(ii) Explain the process of electroplating.

(iii) What do you mean by electrolysis and electrolytes?

(iv) Explain why the process of rusting can be called as slow combustion.

(v) Explain with an activity that air is necessary for combustion.

Q4. Each question carries 5marks.

(i) Explain the process of electroplating, along with its advantages and uses.

(ii) Clear transparent water is always fit for drinking, do you agree? Explain your answer.

(iii) Explain air pollution and its harmful effects. Also list some important measures to reduce air pollution.

(iv) Explain how combustion takes place in a matchstick.

Ncert Solutions For Class 8th

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