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An electric bell consists of an iron core, on which is wound a wire as a coil. One end of the coil is connected to one terminal of a battery, and the other end to a steel rod that acts like a spring for the hammer touching the screw contact. The other terminal of the battery is connected to the screw contact with a switch in the middle.
Working of an electric bell: Electric current flows through the coil when the switch is ON, and the iron core acts as an electromagnet. The iron core attracts the hammer towards it. The hammer hits the bell and produces a sound. The circuit breaks at the screw contact when the hammer moves towards the iron core. At this point, the iron core ceases to be an electromagnet. The hammer is pulled back to its original position due to the spring action of the steel rod, and then touches the contact again to complete the circuit. The circuit is completed and current flows through the coil again, and the hammer strikes the bell again. The process repeats itself and you hear a ringing sound since the hammer keeps hitting the bell, until the switch is released.

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Why should we take antacid during indigestion

Posted by Ayushi Pathak 7 years, 6 months ago

CBSE > Class 07 > Science

1 answers

Edithal Anish 7 years, 6 months ago

As it is a basic solution and neutralises acidic reaction

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What is Biogas?

Posted by Secret Superstar 7 years, 6 months ago

CBSE > Class 07 > Science

1 answers

Secret Superstar 7 years, 6 months ago

The gas that is produced by decomposition of sludge by the bacteria is known as Biogas.

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How would you improve sanitation conditions of an area?

Posted by Secret Superstar 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

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What is electromagnet?

Posted by Asmita Gusain 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Raina Kushwah 7 years, 6 months ago

A soft piece of iron wrapped with insulated wire .When the electric current flows through it ,it acts like a magnet .It is called electromagnet.

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Rachit Shukla 7 years, 6 months ago

It is a metal with electrical power..

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What is the main source of el mom z

Posted by Bhumi Kumari 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

What is vegetative propogation

Posted by Abhishek Shinde 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Rachit Shukla 7 years, 6 months ago

Reproduction in plants by the vegetative parts of the plant like stem roots is called vegetative propagation..

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Royal Girl 7 years, 6 months ago

reproduction of new individual by the vegetative part of parents in plants are called vegetative propagation?

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Hhh

Posted by Yash Pawar 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

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Marada kasy banti h

Posted by Deksh Deksh 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

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Which soil is riches in human

Posted by Mainudeen Mainudeen 7 years, 6 months ago

CBSE > Class 07 > Science

3 answers

Nishi Garg 7 years, 6 months ago

Sorry humus

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Nishi Garg 7 years, 6 months ago

Re u saying g which soil is rich in hymus

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Joan Mariam Jijo 7 years, 6 months ago

What r u saying????

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Platelet

Posted by Alok Thakur 7 years, 6 months ago

CBSE > Class 07 > Science

1 answers

Joan Mariam Jijo 7 years, 6 months ago

Platelet helps in clotting of blood

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ANSWER

Regeneration

Posted by Shrishti Singh 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

what is energy?

Posted by Ranjan Kumar 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

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What is sludje

Posted by Aman Dwivedi 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Royal Girl 7 years, 6 months ago

the solid such as faces settled down in large circular tank is called sludge

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Ayisha Dhilna 7 years, 6 months ago

Sludje or SIudge . did you mean Sludge?

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What is a reflection of light ?

Posted by Vibhuti Kumari 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Rachit Shukla 7 years, 6 months ago

When the beam of light changes its direction when it falls on any Shiny object is called reflection of light..

1Thank You

Ayisha Dhilna 7 years, 6 months ago

A mirror changes the direction of light that falls on it.This change of direction by a mirror is called reflection of light.

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Give me all Images of concave,convex and also in the lenses

Posted by Aditya Narayan 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

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What is NaHCO3

Posted by Hargun Kaur 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Rachit Shukla 7 years, 6 months ago

Nhc O3 is baking soda or sodium carbonate

1Thank You

Prayag Verma 7 years, 6 months ago

Baking soda(sodium hydrogen carbonate)

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What is mean by sexual reprodution

Posted by Sanskar Kemdarne 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Rachit Shukla 7 years, 6 months ago

When the male and female reproductive organ unite to produce new individual is called sexual reproduction..

2Thank You

Karsh Singh 7 years, 6 months ago

Reproduction in which two parents are needed to form a new individual

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Why banana is not called true fruit

Posted by Urvi Chadha 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

What is a electric fuse

Posted by Siddhant Shandilya 7 years, 6 months ago

CBSE > Class 07 > Science

1 answers

Abhishek Ray 7 years, 6 months ago

The electric bulb fuses because it's filament is broken

1Thank You

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A car travel 80 km in two hours it's speed

Posted by Misti Dadhich 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Aditya Raj 7 years, 6 months ago

Speed= distance/ time. So,80/2=40

2Thank You

Scb Fx Hfjgbc Vb N 7 years, 6 months ago

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Name some plant product food?

Posted by Khundongbam Dolen 7 years, 6 months ago

CBSE > Class 07 > Science

1 answers

Royal Girl 7 years, 6 months ago

honey nuts mashrooms etc.

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Why acids are sour ?

Posted by Piyush Bansal 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Himanshu Garg 7 years, 6 months ago

Because it contain acidity

1Thank You

Urvi Chadha 7 years, 6 months ago

Because of the hydrogen ion concentration

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Short note on rearing of silk worm

Posted by Kavya Khemka 7 years, 6 months ago

CBSE > Class 07 > Science

2 answers

Ashu And Vishu Sharma 4 years, 8 months ago

Write a very short note on rearing of silkmoth for class 7th

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Yogita Ingle 7 years, 6 months ago

Sericulture, or silk farming, is the rearing of silkworms for the production of raw silk. Silkworms are reared under suitable conditions of temperature and humidity to obtain silk threads from their cocoons. The female silk moth lays hundreds of eggs.
These are stored on strips of cloth or paper. Mulberry leaves are the staple diet of silkworms. When the mulberry tree bears a fresh crop of leaves, the eggs are warmed suitably so that the larvae hatch from them.
The larvae, caterpillars or silkworms are then stored in clean bamboo trays and are fed freshly chopped mulberry leaves. They eat day and night, and grow to enormous sizes.
The bamboo trays are provided with small racks or twigs to which the cocoons can be attached.
This happens usually after 25 to 30 days when the caterpillars stop feeding and move to the twigs to spin cocoons. The silk moth develops inside these cocoons.

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Plant don't use all the water available to them from thesoil. Much of it is off by transpiration. Why do they take in so much of water from the soil?

Posted by Gaurav Gaurav 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

explain an activity to prove that soil contain watee

Posted by Syeda Syeda 7 years, 6 months ago

CBSE > Class 07 > Science

0 answers

ANSWER

Which think make blood red

Posted by Harshav Dhawan 7 years, 6 months ago

CBSE > Class 07 > Science

4 answers

Jyoti Sehrawat 7 years, 6 months ago

Haemoglobin makes the blood red

1Thank You

Chandrima Ray 7 years, 6 months ago

Haemoglobin is a red pigment which is red in colour for content of iron and protein in it hens blood contains haemoglobin which gives it the red colour

1Thank You

Himanshu Garg 7 years, 6 months ago

Haemoglobin make the blood red .And red blood carrying oxygen rich blood.

2Thank You

Akshit Sharma 7 years, 6 months ago

Within the red blood cells there is a protein called hemoglobin. Each hemoglobin protein is made up subunits called hemes, which are what give blood its red color. More specifically, the hemes can bind iron molecules, and these iron molecules bind oxygen.

4Thank You

ANSWER

Other name for covex lens

Posted by Rohan Mishra 7 years, 6 months ago

CBSE > Class 07 > Science