Some Natural Phenomena quiz

When a plastic comb is rubbed on dry hair, it acquires:

Two like charges:

The device used to detect whether an object is charged is a:

The process of transferring charge from a charged object to the Earth is called:

Which of the following is the safest place during a thunderstorm?

Earthquakes are recorded by an instrument called a:

The magnitude of an earthquake is expressed on the:

Earthquakes are caused mainly by:

A lightning conductor protects a building by:

The Bhuj earthquake occurred in the state of:

Why does a charged balloon stick to a wall? (2 marks)

What are positive and negative charges? Which kind of charge is acquired by a glass rod rubbed with silk? (2 marks)

Why do the aluminium foil strips of an electroscope move apart when a charged object touches the clip? (2 marks)

How does charge build up in thunderclouds? (2 marks)

Why should we not take a bath or use a landline phone during a thunderstorm? (2 marks)

Why is it dangerous to stand near electric poles or under tall trees during lightning? (2 marks)

Name three regions of India that are in high seismic zones. (2 marks)

Why are buildings in earthquake-prone areas built with light materials such as wood and mud? (2 marks)

What is a tsunami? How is it related to earthquakes? (2 marks)

What should you do if you are indoors during an earthquake? (2 marks)

The time between seeing a lightning flash and hearing the thunder is 4 seconds. Taking the speed of sound in air as 340 m/s, find the distance of the lightning. If the gap had been 10 seconds, how far away would it be? (3 marks)

An earthquake of magnitude 6 has about 1000 times more destructive energy than one of magnitude 4. How many times more destructive energy does an earthquake of magnitude 8 have compared with one of magnitude 4? (3 marks)

Light travels at about 3,00,000 km/s and sound at about 340 m/s in air. Lightning strikes 1.7 km away. Find the time taken by the sound of thunder to reach you, and show that the time taken by light is negligible. (3 marks)

A town has 2,400 buildings. A survey finds that 30% are not earthquake-resistant. How many buildings need to be strengthened? If the town can strengthen 90 buildings a year, how many years will it take? (3 marks)

In an experiment, two balloons rubbed with wool repelled each other, a balloon and a plastic straw rubbed with the same woollen cloth repelled each other, and a balloon and a glass rod rubbed with silk attracted each other. What kind of charge does each object carry if the balloon is negatively charged? Explain your reasoning. (3 marks)

Read the passage and answer the questions. Paheli rubbed a plastic refill with polythene and touched it to the paper clip of her home-made electroscope. The aluminium strips moved apart. When she touched the clip with her hand, the strips collapsed. (i) Why did the strips move apart? (ii) Why did they collapse when she touched the clip? (iii) Name this process of removing charge. (5 marks)

Read the passage and answer the questions. Ramesh was playing cricket in an open ground when dark clouds gathered and lightning began to flash. His friend wanted to take shelter under a tall tree in the middle of the ground. (i) Why is standing under a tall tree dangerous during lightning? (ii) What should the boys do if no safe building is nearby? (iii) Why should they not hold metal objects such as bats with metal grips or umbrellas? (5 marks)

Read the passage and answer the questions. A tall temple in a hill town was often struck by lightning, damaging its dome. Engineers fixed a pointed metal rod at the top, connected by a thick copper strip running down the wall to a metal plate buried deep in moist earth. (i) What is this device called? (ii) How does it protect the temple? (iii) Why is the metal plate buried in moist earth? (5 marks)

Read the passage and answer the questions. On 26 January 2001, a severe earthquake struck Bhuj in Gujarat, killing thousands of people and destroying many buildings. Scientists said the region lies in a high-risk seismic zone. (i) What causes an earthquake like this? (ii) Why did so many buildings collapse? (iii) Suggest two ways to reduce damage in future earthquakes. (5 marks)

Read the passage and answer the questions. In a school earthquake drill, students were taught to drop to the floor, take cover under a strong desk and hold on until the shaking stopped. They were told not to use lifts and to move to an open area after the shaking stopped. (i) Why should students take cover under a strong desk? (ii) Why should lifts not be used during an earthquake? (iii) Why should they move to an open area afterwards and stay away from walls, trees and poles? (5 marks)

Draw a labelled diagram of a simple electroscope. Explain how it works, how charge can be transferred from one object to another, and what happens when the electroscope is earthed. (6 marks)

Draw a labelled diagram showing the formation of lightning. Explain how charges separate and collect in clouds, what an electric discharge is, and how lightning conductors protect buildings. (6 marks)

Draw a labelled diagram of the layers of the Earth showing the crust broken into plates. Explain how the movement of plates causes earthquakes and why certain regions are more prone to them. (6 marks)

Draw a labelled diagram of a seismograph or of the recording it produces. Explain the Richter scale and compare the destructive energy of earthquakes of magnitudes 4, 6 and 8. (6 marks)

Design a labelled safety chart for students showing what to do and what not to do during lightning and during an earthquake. Give at least four points for each, with reasons. (6 marks)