NCERT Class VIII Science Solutions: Chapter 15-Some Natural Phenomena Part 3

Download PDF of This Page (Size: 228K)

Question 13:

If a charged plastic straw is brought near another uncharged plastic straw, what will happen?

Answer:

The two will attract each other

Question 14:

The aluminium strips in an electroscope as shown in fig are replaced by plastic strips and a charged body is brought in contact with the metal clip. What will happen?

As showing in fig is a aluminium strips in an electroscope

The Aluminium Strips in an Electroscope

As showing in fig is a aluminium strips in an electroscope

Answer:

No divergence of strips will take place.

Question 15:

Plastic straws A and B are rubbed with dry cotton cloth. What will happen if they are brought near each other?

Answer:

They will repel each other.

SHORT ANSWER QUESTIONS

Question 16:

During the construction of a building the lightning conductor was left hanging in the air by mistake. Would the lightning conductor be still effective? Explain.

Answer:

No, it will not be effective. Since lightning conductor was not connected properly to the earth, therefore, the charge will not pass through to the earth.

Question 17:

If air and cloud were good conductors of electricity, do you think lightning could occur? Explain.

Answer:

No, it will not occur. The charge separation cannot take place in conductors. Therefore charges will not accumulate on clouds and so lightning cannot take place.

Question 18:

Identify the lightning conductor and the copper plate in

As showing in fig is a find the lightning conductor and copper plate

Find the Lightning Conductor and Copper Plate

As showing in fig is a find the lightning conductor and copper plate

Answer:

A is the lightning conductor and B is the copper plate.