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Answer is To store the charge

Place copper sheet around the leaves of an electroscope. Touch the nob with a charged, body. Opposite charge is formed on the leaves. Opposite charge of it is formed inside the sheet and the same charge is formed outer surface of the sheet. Now the sheet is earthed, the charge on outer surface will be disappeared.

1. repel 

2. attract 

3. attract

They will repel. Same charges repel each other.

No. Only certain pairs of substances get charged on rubbing.

a. Glass 

b. Wool 

c. Ebonite 

d. From wool to rubber rod 

e. Rubber rod

Charge cannot be developed on a copper rod because only certain pairs of substances give rise to electric charge, on rubbing.

The charge developed due to friction is called 1 static electric charge because the charge remains still on the object.

Even though all the lightning will not affect the building, if there is lightning conductor the opposite charge of that in the clouds is induced on the pointed end of the conductor. If there is no earthing the flow of electron will be from the building to the conductor or to the building which causes accident

We can use other metals than gold in gold leaf electroscope.

1. Only thing is that metal should be malleable and good conductor of electricity. 

2. But the best is gold only because we can make extremely thin leaves of gold so even very small charge also can be detected.

The leaves of a gold leaf electroscope fly apart when a charged body touches its disc because like charges develop on both the leaves and hence they repel each other.

i. True

ii. False. 

An atom does not have any charge

iii. False. 

When two substances are rubbed on each other unlike charges are developed on each

iv. True

v. True

a. From glass rod to silk

b. From wool to ebonite

Hacksaw blade. Because it is metal

• Do not operate electrical equipments
• Do not lean on the wall of the house.
• Do not stand holding windows bar or grill
• Do not stand beneath tall trees
• Do not take shelter under isolated trees

• Do not operate electrical equipment
• Do not lay on the wall of the house.
• Do not stand holding windows bar or grill
• Do not stand beneath tall trees
• Do not take shelter under isolated trees

The dielectric are the insulators used in between the plates of the capacitor to increase its capacity Eg. Plastic, polyester, air, paper

capacitance is the ability to store the charge in it. Its unit is fared(F)

1F = 10⁶ μF(microfarad) 1F = 10¹² μF

(picofarad)

These lorries and trucks have to travel a long distance. Sometimes the friction between rod and tire or vehicle and oil in it produces static electricity. This discharge gathers at one end of the truck and it causes sparking and from it the petrol may catch fire. The iron chains suspended from the body of lorries and trucks provide earthing and help to avoid the hazard.

i. Phenomenon happening is static electricity. When certain objects are rubbed against each other, they produce an electric charge on their surface at the place of friction. This is due to electrons which remain for a short time. This is called static electricity.

ii. In ‘b’, we observe attraction between the charged balloon and the uncharged aluminium ball. In ‘c’, we observe that the charge has been transferred to the aluminium ball and due to the same (like) charge, repulsion is observed.

1. When air and clouds rub against each other in the sky the upper part of some clouds becomes positively charged and the lower side become negatively charged. 

2. When this negative charge at the bottom of the cloud becomes much larger than the charge on the ground, it starts flowing towards the ground in stages, but this doesn’t happen every day. So lightning is not seen every day during the rainy season.

1. Large amount of charges get built up in the clouds in rainy and stormy weather. 

2. Sometimes these charges are transferred to the earth in the form of a bolt of lightning. 

3. Due to iron staff, the charges will be conducted to the earth through iron metal and spread quickly into the ground. 

4. This way farmers are saved from lighting strike.

i. always repulsion

ii. displacement of negative charge

iii. copper

iv. Steel

v. always attraction

vi. charged object

A person struck by lightning should be made to lie in a place where there is good air circulation. In order to prevent blood clotting keep the body warm by massaging. Give artificial respiration and press strongly on the chest to maintain heartbeat and the person must be taken to a hospital immediately

Advantage:

When lightning strikes the antenna it does not affect the house if the antenna pipe is earthed. The electric charge of the lightning goes to the earth through the pipe and so it acts as a lightning conductor.

The person standing under the tree is safer. Electric charge always get concentrated at sharp edges. So more possibility for danger due to lightning is to the man under coconut tree than the. another one

i. False. 

Charges can be transferred from one body to another

ii. True

iii. True

iv. False. 

An ebonite rod rubbed on woollen cloth develops a negative charge

v. False. 

A glass rod rubbed on woollen cloth develops a positive charge

1. Every atom contains smaller particles with either positive or negative charge. 

2. As the number of positively and negatively charged particles in an atom is equal, they neutralize each other. 

3. As a result the atom has no charge.

Following are the characteristics of a static electric charge.

1. The electric charge generated by friction is called frictional electricity. This charge is produced only at the place of friction, hence it is called static electricity. 

2. It remains on the object for a short duration. 

3. The charges of static electricity are absorbed in moist air. 

4. An electrically charged object attracts another object which has no electric charge. 

5. Like charges repel each other. 6. Unlike charges attract each other. 

7. Repulsion is the sure test of the existence of a static charge.

Coal and salt is filled in the pit and also there is a provision for pouring water into it. This helps to spread electric charge quickly into ground and prevent damage.

Due to lightning great damage can occur.

1. It may cause fire. 

2. Person on whom lightning strikes may die also. 

3. It causes more temperature than sun.

Awareness to prevent it:

1. Guide the people to install lightning conductor on tall buildings. 

2. Do not stand on open ground, below a tree, or on a high location during the thunder storms. 

3. Do not use plugged in electrical appliances. 

4. Do not stand near an electric pole, telephone pole or a tower. 

5. Stay in pucca house made of brick and cement. 

6. Stand on only wood, a plastic sheet or sack of jute.

1. Friction causes a charge to develop, because on rubbing, some negative particles are transferred from one substance to the other and the later develops a negative charge.

2. The substance from which particles are removed lose negative charge and hence, it develops a positive charge.

1. To protect from the lightning, we have to put lightning conductor on high rise buildings, 

2. we should not stand under a tree in rainy and stormy weather. 

3. We should not go out with an umbrella in heavy rain, lightning or thunder.

1. The lightning conductor, consists of a long i copper strip with one end forked. This end is ‘ at the highest part of the building. 

2. The other end of the strip is connected to a plate of cast iron. 

3. A pit is dug in the ground, coal and salt are filled into the pit and the iron plate is placed upright in the pit. 

4. There is also a provision for pouring water into it.

5. This helps to spread the electric charge quickly into the ground.

Following measures can be taken to prevent the damage caused by lightning:

1. Always put lightning conductor on tall buildings. 

2. Do not stand on open ground, below a tree or near the electric or telephone pole during rain/ thunder storms. 

3. Do not lean on wired fences. 

4. Do not use plugged in electrical appliances. 

5. Do not swim during thunder storms. 

6. Stay in a pucca house with lightning conductor fitted on it.

Due to lightning strike, great damage can occur. It may cause forest fire and burn down things. Person on whom lightning strikes may die. It causes more temperature than sun.

1. Large amount of charges get built up in the clouds in rainy and storming weather. 

2. Sometimes these charges are transferred to the earth in the form of a bolt of lightning. 

3. Generally lightning strikes tall buildings and trees. If lightning strikes a tree then either the tree may fall or it may catch fire. 

4. In both cases this would be dangerous for anyone standing under the tree, hence it is dangerous to stand under a tree in rainy and stormy weather.

A charged balloon stick to a wall because there is always attraction between a charged object and an uncharged object.

1. High rise buildings are prone to lightning strikes during the monsoon. 

2. When lightning strikes, a tremendous electric charge is transferred to the earth, which may damage the tall buildings. 

3. To prevent this, high rise buildings have a forked metal rod, called a lightning conductor fitted on the top of the building. 

4. The lower end of this rod is buried inside the earth. 

5. If lightening strikes, the electric charge passes through this conductor and goes in to the earth. In this way the building is saved from damage.

When seeds are shaken they get electrically charged and therefore they stick to the neutral walls of the glass.