Worksheet solutions for chapter: Chemical Effects of Electric Current for class 8 are provided below.
(1) Write differences between good conductor and poor conductor.
Differences between good and poor conductor of electricity are tabulated below:-
|Good Conductor||Poor Conductor|
|Materials which allow electricity to pass through them.||Materials which do not allow electricity to pass through them.|
|Eg:- Metals, caustic soda, Tap water, milk etc.||Eg:- Distilled water, rubber , plastic etc.|
(2) Is honey good conductor of electricity?
No, honey is not good conductor of electricity.
(3) Radha is performing a test on three solutions of lemon juice, distilled water and milk. In two solution bulb glow but in one solution bulb does not glow. Can you identify the solutions?
Lemon juice and milk are the good conductors of electricity but distilled water is a poor conductor of electricity. Therefore, lemon juice and milk are the solutions in which bulb glows. Distilled water is that solution in which bulb does not glow.
(4)Fill in the blanks-
(i) Caustic soda is _____ conductor of electricity.
(ii) ____ Bulb can glow in weak current.
(iii) Needle of tester of magnetic effects of current deflates, if material is ______ conductor of electricity.
(i) Caustic soda is good conductor of electricity.
(ii) LED bulb can glow in weak current.
(iii) Needle of tester of magnetic effects of current deflates, if material is good conductor of electricity.
(5) Identify the positive terminal in given figure below:-
The positive terminal is where the greenish blue spot appears.
(6) What is electroplating? Write its use in daily life.
The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.
Electroplating is used in coating of different metals for different purposes.
(i) Chromium is an expensive metal. So it is used only for coating other metals. It does not corrode and resists scratches. Therefore, chromium plating is done on many objects as bath taps, kitchen gas burners, car parts, furniture etc.
(ii) Less expensive ornaments also shines after electroplating with gold or silver. These ornaments look like original but in real these are not real.
(iii)The tin cans used for the food storage are also electroplating of tin on iron. Tin is less reactive than iron. Therefore, it is useful for food storage.
(iv) Iron is protected by applying zinc coating on it. Then, zinc coated iron is used in making bridges and automobiles.
(7) Raju is trying to glow a bulb. He is using circuit which is given below:-
Can you find his mistake?
Yes, he is trying to flow electricity through a rubber rod. Rubber is poor conductor of electricity. Therefore, bulb is not growing. He will have to use a metal rod instead of plastic rod to glow bulb.
(8) What will you do if bulb will glow dim in a good conductor solution?
If bulb will glow dim in a good conductor solution we will replace that bulb by LED bulb. LED bulb can glow in weak current.
(9) What is electrode?
An electrode is a solid electrical conductor that carries electric current into nonmetallic part of a circuit.
(10) Which type of solutions conduct electricity?
Acids, bases and salt solutions conduct electricity.