CBSE VIII

CBSE VIII Science Set - 1

Question 1

When electric current is passed through water containing acid, ____ gases are produced.
A) hydrogen and oxygen
B) hydrogen and ozone
C) oxygen and hydrogen peroxide
D) hydrogen peroxide and ozone

Question 2

When a soluble metallic salt is added to water, its electrical conductivity decreases.
A) True
B) False

Question 3

Materials that allow electricity to pass through them are called ____.
A) insulators
B) conductors
C) resistors
D) testers

Question 4

Materials that do not allow electricity to pass through them are called ____.
A) insulators
B) capacitors
C) conductors
D) resistors

Question 5

A tester is used to test the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows bright for liquid A, while it glows very dimly for liquid B. We can conclude that liquid A is a better conductor than liquid B.
A) True
B) False

Question 6

The device used to test whether a particular material allows electric current to pass through it or not is a ____.
A) tester
B) resistor
C) capacitor
D) battery

Question 7

While checking your tester, do not join its free ends for more than a few seconds, otherwise the cells of the battery will drain very quickly.
A) True
B) False

Question 8

Which of the following liquids is a poor conductor of electricity?
A) Lemon juice
B) Vinegar
C) Sugar solution
D) Salt solution

Question 9

Which amongst the following is a poor conductor of electricity?
A) Alcohol
B) Common salt solution
C) Copper sulphate solution
D) Aqueous solution of HCl

Question 10

Why doesn't the bulb of a tester glow sometimes even though the material may be a conductor?
A) The current through the circuit is too weak.
B) The current through the circuit is sufficient.
C) The filament gets heated to a very high temperature.
D) The conductor is weak.