NCERT Class 8 Science Chapter 14 Chemical Effects of Electric Current Extra Questions and Answers
Class 8 Science Chapter 14 Extra Questions and Answers – Chemical Effects of Electric Current. Here in this Page Class VIII Students can Learn Extra Questions & Answer 14th Chapter Science fully Inside.
We Provided Here Chemical Effects of Electric Current Science Chapter 14 Long Answer Type Question, Very Short Type Questions (VSA) / MCQ Type Questions, Short Type Questions (SA).
1) Fill in the blanks:
a) ____ is a good conductor of electricity. (Copper)
b) Salted water is a ____ conductor. (Good)
c) The passage of an electric current through a conducting solution causes _____ reactions. (Chemical)
2) Multiple choice questions:
a) ____ is a poor conductor of electricity?
a) Plastic b) Copper
Ans. a) Plastic
b) Distilled water is a ____ conductor?
a) Poor b) Good
Ans. a) Poor
c) The process of depositing a layer of any desired metal on another material by means of electricity is called _____?
a) Electroplating b) Electricity generation
Ans. a) Electroplating
3) Answer the following questions:
a) Explain why tin cans are made by electroplating tin onto iron.
Ans. Tin cans, used for storing food, are made by electroplating tin onto iron. Tin is less reactive than iron. Thus, food does not come into contact with iron and is protected from getting spoilt.
b) Why electroplating is very useful process? Give an example.
Ans. Electroplating is very useful process. It is widely used in industry for coating metal objects with a thin layer of a different metal. The layer of a different metal deposited has desired property, which the metal of the object lacks.
For example, Iron is used in bridges and automobiles to provide strength. However, iron tends to corrode and rust. So, a coating of zinc is deposited on iron to protect it from corrosion and formation of rust.
4) Mark your answer as per the codes provide below:
a) A: Distilled water is a poor conductor of electricity.
R: Distilled water is free of salts.
I.) Both A and R are true and R is the correct explanation of A.
II.) Both A and R are true but R is not the correct explanation of A.
III.) A is true but R is false.
IV.) A is false but R is true.
V.) Both A and R are false.
Ans. I. Both A and R are true and R is the correct explanation of A.
b) A: We use an LED in place of the electric bulb in the tester.
R: LED glows even when a weak electric current flows through it.
I.) Both A and R are true and R is the correct explanation of A.
II.) Both A and R are true but R is not the correct explanation of A.
III.) A is true but R is false.
IV.) A is false but R is true.
V.) Both A and R are false.
Ans. I. Both A and R are true and R is the correct explanation of A.
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5) You may use an LED in place of the electric bulb in the tester. LED glows even when a weak electric current flows through it. There are two wires (called leads) attached to an LED. One lead is slightly longer than the other. Remember that while connecting to a circuit, the longer lead is always connected to the positive terminal of the battery and the shorter lead is connected to the negative terminal of the battery.
a) There are ____ wires attached to an LED.(Two)
b) The _____ lead is connected to the negative terminal of the battery.(Shorter)
c) While connecting to a circuit, the longer lead is always connected to the _____ terminal of the battery. (Positive)
More extra Questions & Answers
Q.1] fill in the blanks
1] the process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.
2) Most liquid’s that can conduct electricity are acid, base and salt solution .
3) When the liquid between the two ends of the tester allows the electric current to pass, the Circuit of the tester becomes complete.
4) Distilled water is a poor conductor of electricity.
5)When an electric current is passed through the copper sulphate solution, copper sulphate dissociates into copper and sulphate.
2] Say whether the following statements are true or false
1] plastic is a poor conductor of electricity.
True
2] lemon juice is a good conductor of electricity.
True
3] when salt is dissolved in distilled water ,we do not obtain a salt solution.
False
Q.3] answer the following
1] what is the use of iron?
Answer – iron is used in bridges and automobiles to provide strength.
2] explain testing conduction of electricity.
Answer – I] when the liquid between the two ends of the tester allows the electric current to pass, the Circuit of the tester becomes complete and current flows in the circuit resulting into glowing of bulb.
II] when the liquid does not allow the electric current to pass, the Circuit of the tester is not complete and the bulb does not glow.
3] explain the term electroplating.
Answer – I] the process of depositing a layered of desired metal on another material by means of electricity is called electroplating.
II] it is widely used in industry for coating metal objects with a thin layer of different metal.
III] this layer has some desired property, which the metal of the object lacks.
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