ch 14 learning science Can anyone send Cordova learning science ch 14 only pictures l
Chapter is chemical effects of electric current.
Plz send
Answers
Answer:
Question 1.
What are good conductors?
Answer:
The substances that conduct electricity through them are called good conductors.
Question 2.
What are insulators or poor conductors?
Answer:
The substances that do not conduct electricity through them are poor conductors or insulators.
Question 3.
Give four examples of conductors.
Answer:
Copper, iron, aluminium and brass.
Question 4.
Give four examples of insulators.
Answer:
Air, wood, rubber and plastic.
Question 5.
Name two metal objects which have a coating of another metal.
Answer:
Handlebars of bicycles, bathroom taps.
Question 6.
What do we get on electrolysis of acidified water?
Answer:
Hydrogen and oxygen gas.
Question 7.
Is air a bad or good conductor?
Answer:
A bad conductor.
Question 8.
Which metal is plated on handle bars of cycles and rim of wheels?
Answer:
Chromium
Question 9.
What is the full form of LED?
Answer:
Light Emitting Diode.
Question 10.
How do we check the electric current?
Answer:
We check the electric current by using a tester.
Question 11.
Which part of an atom is responsible for flow of current?
Answer:
Electron
Question 12.
Why do most liquids conduct electricity?
Answer:
Due to the presence of ions in them, most liquids conduct electricity.
Question 13.
An LED is more efficient device than a bulb. Why?
Answer:
LED is more efficient because it can glow even when a weak or less current flows through it.
Question 14.
Do lemon juice or vinegar conduct electricity?
Answer:
Yes, they conduct electricity.
Question 15.
How is conductivity of liquids tested?
Answer:
By using a tester.
Question 16.
Is water from taps, handpumps, wells and ponds a good conductor?
Answer:
Yes, water from these sources is a good conductor.
Question 17.
What makes distilled water a good conductor?
Answer:
Salts when mixed with distilled water make it a good conductor.
Question 18.
Why is a layer of zinc coated over iron?
Answer:
To prevent iron from corrosion and rust.
Question 19.
Will the solution of sugar in distilled water conduct electricity?
Answer:
No
Question 20.
Why is tin electroplated on iron to make cans used for storing food?
Answer:
Tin is less reactive than iron. Tin coating prevents food from coming in contact with iron and thus pre¬vents it from getting spoiled or corroded.
Question 21.
Why we ifse chromium electroplating on taps and bars of bicycle instead of silver and gold?
Answer:
Silver and gold are very expensive comparatively to chromium.
Question 22.
What type of effect of current do the deposits of metal on electrodes show?
Answer:
Chemical effect
Question 23.
What effect of current does electroplating show?
Answer:
Chemical effect
Question 24.
Which effect of current causes the bulb to glow?
Answer:
Heating effect
Question 25.
Which part of the bulb glows?
Answer:
Filament
Question 26.
Name the three effects of electric current.
Answer:
Heating, magnetic and chemical effect.
Question 27.
How can the magnetic effect of current be checked?
Answer:
By using magnetic compass.
Question 28.
What do we see when the compass needle is brought near a wire in which current is flowing?
Answer:
The needle deflects.
Question 29.
What is electroplating?
Answer:
Deposition of thin layer of a metal over other metal by electrolysis is called electroplating.
Explanation: