Science Question Answer (3 Marks)

There are two types of charges: Positive charge and negative charge. Like charges repel each other and unlike charges attract each other. A charged balloon repels another charged balloon because like charges repel each other. A charged balloon attracts an uncharged balloon by the process of electric induction. The charged balloon produces opposite charges in the nearer end of the uncharged balloon.

In order to find out if an object is charged or not, we can test it by using an electroscope.

1. When the object is touched with the metal cap of an electroscope, both the metal cap and the leaves acquire the charge due to conduction. As a result of.
2. As a result of both, the leaves of the electroscope will have the same charge. It will cause the leaves to diverge showing that the object was charged,

as shown in the pic:

We must protect ourselves in the following ways:

• We must take shelter under the table and should stay until the shaking stops.
• We must stay away from the heavy objects to avoid them to fall on us.
• If we are in bed we must stay in it and should protect our head with a pillow.

We must protect ourselves from lightening in the following ways:

• We must find a safe place to stay. A house or building are safe to stay in. If we are in a car or a bus, we must keep the windows and doors of the vehicle shut.
• If there is no shelter available, we must remain in the squat position.
• We must avoid the use of telephone cords, electrical wires and metal pipes.
• Bathing should be avoided during thunderstorms to avoid contact with running water.
• Electrical appliances like computers, TVs, etc., should be unplugged.

The electric charges generated by rubbing are static electric charges. These electric charges remain bound on the surface of the charged object. When a glass rod is rubbed with silk, some of the electrons from the glass atoms are transferred to silk. Due to the deficiency of electrons in the glass atoms, it becomes positively charged. Whereas the silk has acquired electrons, it becomes negatively charged. Iron rod is a conductor. As soon as we charge an iron rod by rubbing with another material, the electric charge flow through our hand and body and flows into the earth. As a result, the iron rod remains un-charged by rubbing, if held by hand.

The various effects of earthquakes are following:

• Earthquakes can cause immense damage to buildings, bridges, dams and people.
• There can be a great loss to life and property.
• The earthquakes can cause floods, landslides and tsunamis.

1. When a glass rod is rubbed with a silk cloth, it acquires positive charge. When it is touched with the metal top of an electroscope, both the metal top and leaves acquires a positive charge due to conduction. As a result of the positive charge on both the leaves, the divergence of leaves takes place.
2. After rubbing the plastic comb, it acquires negative charge. When it is touched with the metal cap of an electroscope, both the metal cap and the leaves acquire negative charge due to conduction. As a result of negative charge on both the leaves, divergence of leaves takes place.

There are a number of ways to measure the magnitude of an earthquake. But, the Richter magnitude scale (often shortened to Richter scale) is the most common standard of measurement for earthquakes. The Richter scale is used to rate the magnitude of an earthquake, that is the amount of energy released during an earthquake.

Richter magnitude	Earthquake effects
0-2	Not felt by people
2-3	Felt little by people
3-4	Ceiling lights swing
4-5	Walls crack
5-6	Furniture moves
6-7	Some buildings collapse
7-8	Many buildings destroyed
8-Up	Total destruction of buildings, bridges and roads