Earthing

Q.

Differentiate between Static Electricity and Current Electricity.

Q.

A negatively charged rod is brought near an uncharged, grounded electroscope. Which of the following statements is true?

1. The positive charge flows from the electroscope to the ground

2. The positive charge flows from the ground to the electroscope.

3. The negative charge flows from the electroscope to the ground

4. The negative charge flows from the ground to the electroscope.

Q.

What is earthing? Why earthing is provided in the buildings? [2 MARKS]

Q. Choose the correct option:
Statement 1: Earthing is the process of transferring positive charge from the charged object to the Earth.
Statement 2: Earthing is the process of transferring negative charge from the charged object to the Earth.

1. Statement 1 is true, statement 2 is false
2. Statement 1 is false, statement 2 is true
3. Both statements are true
   
4. Both statements are false
   

Q.

What happens when earthing is not done for a lightning conductor?

1. The lightning charges will not be attracted to the conductor

2. The lightning will find a way to neutralize itself

3. Lightning will not occur

4. It will transfer the charges to the air surrounding the conductor.

Q.

Describe with the help of a diagram an instrument which can be used to detect a charged body. [5 MARKS]

Q.

Earthing is provided for electrical appliances in a building to protect it from ______.

1. earthquakes

2. heavy rainfall

3. leakage of electric current

4. inducing excess current

Q. When a body having an imbalance of electrons in it comes in contact with earth through a conducting medium, the earth balances electrons in it by:

1. Taking out the extra electrons from the body.
2. Giving the required number of electrons to the body.
3. Giving neutrons to the body to make it neutral.
4. Giving protons to the body when the body is negatively charged.

Q.

Question 15

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

Q.

What is the reason behind the generation of static electricity by rubbing comb on hair?

1. Friction between comb & hair

2. Induction between comb & hair

3. Chemical reaction between hair and comb

4. By a battery connected to comb

Q.

Fill in the following blanks with suitable words :

(a) Like charges ........ ; unlike charges ...........

(b) Rubbing glass with silk makes a .......... charge on the glass.

(c) Combing your hair makes a ........ charge on the comb.

(d) The negatively charged particles which are transferred from one object to another during charging by friction is called .......

(e) The charging of an object by rubbing it with another object is called charging by ........

(f) In an electroscope, the aluminium leaves diverge because like charges .........

(g) ......... is provided in buildings to protect us from electric shocks due to any leakage of electric current.

(h) Lightning is nothing but an ......... spark.

(i) Each fragment of earth's crust is called a ........

Q.

Why is the metal covering of an electrical appliance earthed?

Q.

The process of transferring charge from a charged body to the earth is called as ____.

1. Discharging

2. Hydrolysis

3. Electrolysis

4. Earthing

Q.

Explain the working of the lightning rods.

Q. The removal of excess charge on a body is called ______.

1. induction
2. magnetising
3. charging
4. discharging

Q.

What is an electroscope ? Draw a labelled diagram of an electroscope and explain its working.

Q.

Why must the plastic or rubber coverings from the ends of wires be removed before making connections? What is the covering called?

Q. What is earthing? Why is it important to provide an earthing connection to a lightning conductor?

Q. Which of the following statements are true in regards to earthing?

1. It protects us from electrical shocks.
2. It is the exchange of charge between two charged bodies.
3. It is the principle behind the working of an electroscope.
4. Lightning conductors involve in the process of earthing.

Q.

What will happen if a lightning conductor system is made in such a manner that it just touches the ground?

1. It will give rise to ground currents

2. It will still work as intended

3. The lightning charges would not be attracted to the conductor at all.

4. The conductor would be destroyed as the charges have no place to go.

Q. Electrical wires generally found in our homes have a plastic covering for safety purposes.

1. False
2. True

Q. Due to charging by friction, negatively charged particles accumulate at the bottom of clouds.

1. False
2. True

Q.

Question 28

If the metal clip used in the electroscope is replaced by an ebonite rod and a charged body is brought in contact with it, will there be any effect on the aluminium strips? Explain.

Q. The process of transferring a charge from a charged body to the Earth is called .

1. earthing
2. electrocution
3. hydrolysis
4. electrolysis

Q.

Fill in the blanks
(a) The object to be electroplated is taken as ___ electrode.

Q.

What is the objective of providing earthing in lightning conductors?

1. To dissipate the heat of a lightning strike

2. It enables the charges to be distributed to the earth

3. To provide a high resistance path to prevent leakages to the ground.

4. To attract lightning

Q.

What happens when a negatively charged body is placed on the ground?

1. The Earth takes away excess electrons from the body to neutralise the body.

2. The Earth supplies protons to neutralise the body.

3. The body charges the Earth negatively.

4. Nothing happens.

Q.

If you slide out of a car seat on a cold, dry day, you get an electric shock when you touch the car body. If you hold on to the body of the car and slide out, this does not happen. Why is this so?

Q. A positively charged body is brought in contact to an uncharged gold leaf electroscope, then:

1. No charge is induced in the leaves
2. Positive charge is induced in both the leaves
3. Negative charge is induced in both the leaves
4. Positive charge is induced in one leaf and negative in the other

Q. If plus sign (+) denotes the positive electrode and minus sign (-) denotes the negative electrode, then which of the following statement is correct for an iron spoon to be copper plated?

1. Iron spoon (+), copper plate (-), Iron sulphate electrolyte
2. Iron spoon (-), copper plate (+), Iron sulphate electrolyte
3. Copper plate (-), Iron spoon (+), Copper sulphate electrolyte
4. Copper plate (+), Iron spoon (-), Copper sulphate electrolyte