Wednesday, 24 February 2021

CBSE Class 8 Science - MCQ and Online Tests - Unit 14 - Chemical Effects of Electric Current

CBSE Class 8 Science – MCQ and Online Tests –  Unit 14 – Chemical Effects of Electric Current

Every year CBSE students attend Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standards’ subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these, our students can identify their weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly


 

CBSE Class 8 Science – MCQ and Online Tests – Unit 14 – Chemical Effects of Electric Current

Choose the correct option.

Question 1.
An electric lamp glows due to
(a) heating effect
(b) magnetic effect
(c) chemical effect
(d) physical effect

Answer

Answer: (a) heating effect


Question 2.
Electroplating prevents
(a) corrosion
(b) passing of current
(c) dissociation
(d) shining

Answer

Answer: (a) corrosion


Question 3.
An electric current can produce
(a) heating effect
(b) chemical effect
(c) magnetic effect
(d) all of these

Answer

Answer: (d) all of these


Question 4.
Pure or distilled water is a
(a) poor conductor
(b) good conductor
(c) both (a) and (b)
(d) none of these

Answer

Answer: (a) poor conductor


Question 5.
Which of the following is a good conductor?
(a) Brick
(b) Steel
(c) Plastic
(d) Cotton

Answer

Answer: (b) Steel


Question 6.
Polythene is
(a) a conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these

Answer

Answer: (b) an insulator


Question 7.
Electroplating is based on
(a) heating effect of electricity
(b) chemical effect of electricity
(c) physical effect of electricity
(d) magnetic effect of electricity

Answer

Answer: (b) chemical effect of electricity


Question 8.
Copper is
(a) a good conductor
(b) an insulator
(c) both (a) and (b)
(d) none of these

Answer

Answer: (a) a good conductor


Question 9.
Waste from an electroplating factory must be disposed off
(a) in the nearby river
(b) in the nearby pond
(c) in the nearby cornfield
(d) according to the disposal guidelines of Waste Management Bodies

Answer

Answer: (d) according to the disposal guidelines of Waste Management Bodies


Question 10.
An electrolyte is
(a) a metal
(b) a liquid that conducts current
(c) a non-metal
(d) none of these

Answer

Answer: (b) a liquid that conducts current


Question 11.
Which of the following is a bad conductor of electricity?
(a) Distilled water
(b) Silver nitrate
(c) Sulphuric acid
(d) Copper sulphate

Answer

Answer: (a) Distilled water


Question 12.
Which of the following does not conduct electricity?
(a) Sugar solution
(b) Vinegar solution
(c) Lemon juice solution
(d) Caustic soda solution

Answer

Answer: (a) Sugar solution


Question 13.
Which is not a non-electrolyte?
(a) Ethyl alcohol
(b) Sodium chloride
(c) Urea
(d) Sodium solution

Answer

Answer: (b) Sodium chloride


Question 14.
The process of depositing a layer of any desired metal on another material by means of electricity is called ___________.
(a) Electric plating
(b) Electroplating
(c) Electric depositing
(d) None of the above

Answer

Answer: (b) Electroplating


Question 15.
Some liquids are good conductors of electricity and some are poor conductors. Which one is a poor conductor?
(a) Acidic solution
(b) Alkaline solution
(c) Common Salt solution
(d) Distilled water

Answer

Answer: (d) Distilled water


Question 16.
Which of the following is not used for electroplating metal articles?
(a) Nickel
(b) Silver
(c) Chromium
(d) Sodium

Answer

Answer: (d) Sodium


Question 17.
Iron objects can be protected by electroplating them with
(a) chromium
(b) nickel
(c) zinc
(d) all of these

Answer

Answer: (d) all of these


Question 18.
In LEDs, the longer lead (wire) is always connected to the _______ terminal
(a) negative
(b) neutral
(c) positive
(d) Any terminal

Answer

Answer: (c) positive


Question 19.
Chromium plating is done on many objects such as car parts, bath taps, kitchen gas stove etc. Why?
(a) It does not corrode but prevents scratches
(b) It looks beautiful
(c) It costs less
(d) Articles can be sold at higher price

Answer

Answer: (a) It does not corrode but prevents scratches


Question 20.
Tap water is a good conductor of electricity while distilled water is not because
(a) Tap water contain salts
(b) Distilled water do not contain salt
(c) Only (a) is correct
(d) Both (a) & (b) is correct

Answer

Answer: (b) Distilled water do not contain salt


Question 21.
When electrodes are immersed in water and electricity passed, the bubbles formed on the positive terminal is actually _______ gas.
(a) Hydrogen
(b) Carbon dioxide
(c) Oxygen
(d) Nitrogen

Answer

Answer: (c) Oxygen


Question 22.
When electrodes are immersed in water and electricity passed, the bubbles formed on the negative terminal is actually _______ gas.
(a) Hydrogen
(b) Carbon dioxide
(c) Oxygen
(d) Nitrogen

Answer

Answer: (a) Hydrogen


Question 23.
Why do we add little dilute sulphuric acid to copper sulphate solution during electroplating?
(a) To increase acidity
(b) To increase conductivity
(c) So that the colour becomes more prominent
(d) To burn copper sulphate

Answer

Answer: (b) To increase conductivity


Question 24.
A coating of _________is deposited on iron to protect it from corrosion and formation of rust
(a) copper
(b) aluminium
(c) Zinc
(d) silver

Answer

Answer: (c) Zinc


Question 25.
Flow of electron is called
(a) electrolyte
(b) electroplating
(c) electrodes
(d) electric current

Answer

Answer: (d) electric current


Share:

0 comments:

Post a Comment

In Article

Definition List

Unordered List

Support