Question 1: Ordinarily, an atom does not have any charge.

Step-by-step solution provided.

Question 3: High rise buildings have lightning conductors.

Step-by-step solution provided.

Maharashtra State Board Class 7 Science & Technology Solutions Chapter 8 Static Electricity - Digest Answers | Maharashtra Board Solutions

Maharashtra State Board Class 7 Science Solutions Chapter 8 Static Electricity

Class 7 Science Chapter 8 Static Electricity Textbook Questions and Answers

1. Choose the correct option and fill in the blanks.
(always repulsion, always attraction, displacement of negative charge, displacement of positive charge, atom, molecule, steel, copper, plastic, inflated balloon, charged object, gold)

Question a.
There is ………….. between like charges.
Answer:
always repulsion

Question b.
…………. is responsible for generation of electric charge in an object.
Answer:
displacement of negative charge

Question c.
A lightning conductor is made of a ……………… strip.
Answer:
copper

Question d.
……………… does not get electrically charged easily by rubbing.
Answer:
Steel

Question e.
There is …………………. when opposite electric charges come near each other.
Answer:
always attraction

Question f.
A ……………… canbe detected with an electroscope.
Answer:
charged object

2. Explain why it is not safe to go out with an umbrella when there is heavy raine lightning or thunder.

Question a.
Explain why it is not safe to go out with an umbrella when there is heavy raine lightning or thunder.
Answer:
Large amount of charges get built up in the clouds in rainy and stormy weather.

3. Answer in your own words.

Question a.
How will you protect yourself from lightning?
Answer:

Question b.
How are charges generated?
Answer:

Question c.
In the lightning conductor, what provision is made for spreading the electricity into the ground?
Answer:

Question d.
Why do farmers stick an iron staff into the ground while working in the field in rainy conditions?
Answer:

Question e.
Why is lightning not seen every day during the rainy season?
Answer:

4. What are the characteristics of a static electric charge?

Question a.
What are the characteristics of a static electric charge?
Answer:
Following are the characteristics of a static electric charge.

5. What is the damage caused by lightning? How will you ereate awareness to prevent it?

Question a.
What is the damage caused by lightning? How will you ereate awareness to prevent it?
Answer:
Due to lightning great damage can occur.

Awareness to prevent it:

Project:

Question a.
Make an electroscope yourself by using a thin aluminium foil and check which substances become electrically charged.

Class 7 Science Chapter8 Static ElectricityImportant Questions and Answers

Question 1 Maharashtra Board Solution

named the electric charges as positive charge and negative charge.

Solution & Step-by-Step Answer:

Benjamin Franklin

Question 2 Maharashtra Board Solution

Each atom contains a stationary charge and moving charges.

Solution & Step-by-Step Answer:

positive, negative

Question 3 Maharashtra Board Solution

Each atom is electrically

Solution & Step-by-Step Answer:

neutral

Question 4 Maharashtra Board Solution

Amber is called in the Greek language.

Solution & Step-by-Step Answer:

electron

Question 5 Maharashtra Board Solution

The charges of electricity are absorbed in moist air.

Solution & Step-by-Step Answer:

static

Question 6 Maharashtra Board Solution

Electrically charged objects uncharged objects.

Solution & Step-by-Step Answer:

attract

Question 7 Maharashtra Board Solution

is used as a test for identifying an electrically charged object.

Solution & Step-by-Step Answer:

Repulsion

Question 8 Maharashtra Board Solution

The property of amber to attract things was named electricity by in 1646 AD.

Solution & Step-by-Step Answer:

Thomas Brown

Question 9 Maharashtra Board Solution

The electric charge generated by stays only as long as the charged object is near to it.

Solution & Step-by-Step Answer:

induction

Question 10 Maharashtra Board Solution

A simple device is used to detect the electric charge on an object.

Solution & Step-by-Step Answer:

gold leaf electroscope

Question 11 Maharashtra Board Solution

Lightning is a form of

Solution & Step-by-Step Answer:

electric charge

Question 12 Maharashtra Board Solution

The gas protects us from the harmful ultra violet rays coming from the sun.

Solution & Step-by-Step Answer:

ozone

Question 13 Maharashtra Board Solution

The is a device used for protection from a lightning strike.

Solution & Step-by-Step Answer:

lightning conductor

Question 14 Maharashtra Board Solution

Due to the energy of the lightning, the oxygen in the air is converted into

Solution & Step-by-Step Answer:

ozone

2. Match the columns:

Question a.

Column ‘A’	Column ‘B’
1. Like charges	a. gold leaf electroscope
2. Unlike charges	b. lightning conductor
3. Copper strip	c. attraction
4. Gold leaves.	d. repulsion

Answer:

Column ‘A’	Column ‘B’
1. Like charges	d. repulsion
2. Unlike charges	c. attraction
3. Copper strip	b. lightning conductor
4. Gold leaves.	a. gold leaf electroscope

Say whether true or false, correct and rewrite the false statement:

Question 1 Maharashtra Board Solution

Charges cannot be transferred from one body to another.

Solution & Step-by-Step Answer:

False. Charges can be transferred from one body to another

Question 2 Maharashtra Board Solution

The word ‘electricity.’ came from the word ‘Elektron’.

Solution & Step-by-Step Answer:

True

Question 3 Maharashtra Board Solution

When an inflated balloon is rubbed on silk, it develops a charge.

Solution & Step-by-Step Answer:

True

Question 4 Maharashtra Board Solution

An ebonite rod rubbed on woollen cloth develops a positive charge.

Solution & Step-by-Step Answer:

False. An ebonite rod rubbed on woollen cloth develops a negative charge

Question 5 Maharashtra Board Solution

A glass rod rubbed on woollen cloth develops a negative charge.

Solution & Step-by-Step Answer:

False. A glass rod rubbed on woollen cloth develops a positive charge

Question 6 Maharashtra Board Solution

If the leaves of the electroscope spread only a little, the charge on them is less.

Solution & Step-by-Step Answer:

True

Question 7 Maharashtra Board Solution

An atom may have either a positive or a negative charge.

Solution & Step-by-Step Answer:

False. An atom does not have any charge

Question 8 Maharashtra Board Solution

When two substances are rubbed on each other, like charges are developed on each.

Solution & Step-by-Step Answer:

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

Question 9 Maharashtra Board Solution

High rise buildings have lightning conductors.

Solution & Step-by-Step Answer:

True

Question 10 Maharashtra Board Solution

It is dangerous to stand under a tree in rainy and stormy weather.

Solution & Step-by-Step Answer:

True

Give scientific reasons:

Question 1 Maharashtra Board Solution

Ordinarily, an atom does not have any charge.

Solution & Step-by-Step Answer:

Question 2 Maharashtra Board Solution

Charge cannot be developed on a copper rod.

Solution & Step-by-Step Answer:

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

Question 3 Maharashtra Board Solution

High rise buildings have lightning conductors.

Solution & Step-by-Step Answer:

Question 4 Maharashtra Board Solution

It is dangerous to stand under a tree in rainy and stormy weather.

Solution & Step-by-Step Answer:

Question 5 Maharashtra Board Solution

Repulsion is a test used for identifying an electrically charged object.

Solution & Step-by-Step Answer:

Question 6 Maharashtra Board Solution

Mustard seeds when shaken vigorously in a glass bottle stick to the sides of the bottle.

Solution & Step-by-Step Answer:

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

Answer the following:

Question 1 Maharashtra Board Solution

Why is the charge developed due to friction called static electric charge?

Solution & Step-by-Step Answer:

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

Question 2 Maharashtra Board Solution

Why does the charge developed by induction disappear quickly?

Solution & Step-by-Step Answer:

The charge developed by induction disappears quickly because it is very weak.

Question 3 Maharashtra Board Solution

Why do the leaves of a gold leaf electroscope fly apart when a charged body touches its disc?

Solution & Step-by-Step Answer:

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.

Draw a neat labelled diagram of Gold leaf electroscope and describe it.

Answer:

Use your brainpower:

Question 1 Maharashtra Board Solution

Do all the objects get charged by rubbing?

Solution & Step-by-Step Answer:

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

Question 2 Maharashtra Board Solution

Why does a charged balloon stick to a wall?

Solution & Step-by-Step Answer:

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

Question 3 Maharashtra Board Solution

Can we use leaves of some other metal instead of gold, in the electroscope? Which properties must that metal have?

Solution & Step-by-Step Answer:

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

Question 4 Maharashtra Board Solution

What kind of damage is caused by a lightning strike?

Solution & Step-by-Step Answer:

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.

Question 5 Maharashtra Board Solution

What measures will you take to prevent the damage caused by lightning?

Solution & Step-by-Step Answer:

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

Question 6 Maharashtra Board Solution

Why is the upper end of the lighting conductor pointed?

Solution & Step-by-Step Answer:

Question 7 Maharashtra Board Solution

Why is coal and salt added to the pit in the ground?

Solution & Step-by-Step Answer:

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.

Observe the given diagram and answer the questions given.

Question a.
Name the phenomenon happening in the diagram and define it
Answer:
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.

Question b.
What do you observe in “b” and “c” part of the diagram?
Answer:
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.

Chapter 8 Static Electricity Solutions