CBSE > Class 09 > Science | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

State laws of motion ?

Posted by Naina Choudhary. 5 years, 7 months ago

1 answers

Pankaj Singh 5 years, 7 months ago

1) Every object in a state of uniform motion will remain in that state of motion unless an external force acts on it. 2) Force equals mass times acceleration[f=m×a ]. 3) For every action there is an equal and opposite reaction.

1Thank You

ANSWER

In equation v=u+at , v is always greater than u. State true or false.

Posted by Riya Jain 5 years, 7 months ago

CBSE > Class 09 > Science

6 answers

Pooja Patil 5 years, 7 months ago

False

0Thank You

Archana Krishnan 5 years, 7 months ago

False.. ( 'v' can either be bigger or smaller than 'u' )

0Thank You

Pankaj Singh 5 years, 7 months ago

False

0Thank You

Sudhanshu Kumar Mishra 5 years, 7 months ago

False

0Thank You

Gopal Sisdodia 5 years, 7 months ago

True

0Thank You

Suraj Lal 5 years, 7 months ago

True

0Thank You

ANSWER

In equation 'v=u+at', is always greater than u

Posted by Riya Jain 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Gopal Sisdodia 5 years, 7 months ago

1Thank You

Ahan Sambhar 5 years, 7 months ago

No, u can also be greater E.g. u=5 m/s a= -5m/s2 and t=1 sec then v= 5 - 5= 0

0Thank You

ANSWER

what is Na

Posted by Sameen Rahiman .P 276 5 years, 7 months ago

CBSE > Class 09 > Science

6 answers

Bhola Bhandari 5 years, 7 months ago

Sodium its atomic no is 7 and mass is14

0Thank You

Paladh Kukreja 5 years, 7 months ago

Sodium Symbol NA

0Thank You

Pooja Patil 5 years, 7 months ago

Sodium

0Thank You

Gopal Sisdodia 5 years, 7 months ago

Sodium

0Thank You

Ritvik Kant 5 years, 7 months ago

sodium eg sodium chloride <common salt>

0Thank You

Laeba Tahreem 5 years, 7 months ago

Sodium

0Thank You

ANSWER

what are the no. of shell n

Posted by Varsha Dass 5 years, 7 months ago

CBSE > Class 09 > Science

8 answers

Bhola Bhandari 5 years, 7 months ago

K l m n

0Thank You

Paladh Kukreja 5 years, 7 months ago

0Thank You

Parveen Kumari 5 years, 7 months ago

0Thank You

Gopal Sisdodia 5 years, 7 months ago

0Thank You

Suraj Kumar 5 years, 7 months ago

Since the formula for finding no. of electrons in the following no. of shell is 2(n)^2 . Where n is no. of shell. So, n shell includes : 2(4)^2=2×16 =32 electrons

0Thank You

Jahanvi Sharma 5 years, 7 months ago

1Thank You

Bhargav Navin 5 years, 7 months ago

2n^2= 2*4^2=32

0Thank You

Bhargav Navin 5 years, 7 months ago

0Thank You

ANSWER

Pless tell me what the paper is comming

Posted by Kashish Arora 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Gopal Sisdodia 5 years, 7 months ago

Final

0Thank You

ANSWER

What is cation & anion ?

Posted by Naina Choudhary. 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Gopal Sisdodia 5 years, 7 months ago

Cation alway + Anion alway -

0Thank You

Yogita Ingle 5 years, 7 months ago

Cations are positively charged ions. They are formed when a metal loses its electrons. They lose one or more than one electron and do not lose any protons. Therefore they possess a net positive charge. Some examples of cations are Calcium (Ca²⁺), Potassium (K⁺), hydrogen (H⁺).

Anions are negatively charged ions. They are formed when non-metal gains the electrons. They gain one or more than one electron and do not lose any protons. Therefore they possess a net negative charge. Some examples of anions are Iodide (I^–), chlorine (Cl^–), hydroxide (OH^–).

1Thank You

ANSWER

What is ion ?

Posted by Naina Choudhary. 5 years, 7 months ago

CBSE > Class 09 > Science

3 answers

Gopal Sisdodia 5 years, 7 months ago

Ion charged atom all time

0Thank You

Aaquib Khan 5 years, 7 months ago

Charged atom is called ion.

0Thank You

Yogita Ingle 5 years, 7 months ago

Metals and non-metals leads to the formation of Compounds that possess charged species. These charged species are called ions.
These charged species can be either positively charged called cation or negatively charged called anion. For instance, In sodium chloride (NaCl), Na exist as cation Na⁺ whereas Cl exist as anion Cl^-.

1Thank You

ANSWER

What is atomicity ?

Posted by Naina Choudhary. 5 years, 7 months ago

CBSE > Class 09 > Science

3 answers

Gopal Sisdodia 5 years, 7 months ago

Atom is present in molecule part element

0Thank You

Yogita Ingle 5 years, 7 months ago

The number of atoms present in a single molecule is termed as its atomicity. It can be classified into three types.

The molecules of many elements are composed of only a single atom of that element. They are termed as monoatomic. For instance, Ar (Argon), He(Helium). So their atomicity is one.
On the other hand the molecules of many elements are composed of two atoms of that element. For instance, oxygen can never exist independently and exist as O₂ molecule known as diatomic So its atomicity is 2.
The molecules of many elements are composed of three atoms of that element. They are termed as triatomic For instance, O₃, CO₂. So their atomicity is 3.
The molecules of many elements are composed of four atoms of that element. They are termed as tetra atomic For instance, P₄, SO₃. So their atomicity is 4.

1Thank You

Neelam Rani 5 years, 7 months ago

The number of atom present in one molecule of an element is called atomicity

5Thank You

ANSWER

How do prepare biology chapters?

Posted by prak****@***** 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Prabh Simran 5 years, 7 months ago

Plz reading and learning the mindmaps (like chart of whole process) you can learnt easily.

0Thank You

David Talukdar 5 years, 7 months ago

Learn about 24 hours

0Thank You

ANSWER

Is carbon dioxide responsible for damaging of ozone layer??

Posted by Asifa Naaz 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Neelam Rani 5 years, 7 months ago

Chloro fluro carbon

0Thank You

Jeevika Harshine 5 years, 7 months ago

One reason

0Thank You

ANSWER

Define 1 watt of power???

Posted by Asifa Naaz 5 years, 7 months ago

CBSE > Class 09 > Science

3 answers

Gopal Sisdodia 5 years, 7 months ago

1J per sec

1Thank You

Neelam Rani 5 years, 7 months ago

1 joule per second

1Thank You

Srinivas Rayakala 5 years, 7 months ago

If an agent works at the rate of 1J then the power of that agent is 1watt

1Thank You

ANSWER

Explain quantum realm

Posted by Tavish Sehgal 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

David Talukdar 5 years, 7 months ago

The quantum realm in physics is the realm where the scale where quantum mechanical effects become important when studied as an isolated system.

0Thank You

ANSWER

Why relative density is diamentionless

Posted by Pandurang Wankhede 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 7 months ago

Relative density is the ratio of density of something to density of a standard.
Relative density is an unitless quantity.

1Thank You

ANSWER

An object freely falling hits the ground where is its kinetic energy transferred and in which form?

Posted by Yash Mishra 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 7 months ago

When an object falls freely towards ground, its kinetic energy transform into different forms of energy:-

Heat energy is produced when an object hits the ground and collides.
Sound or vibration energy is produced due to the collision of the object with the ground.
In deforming the body or the ground.

1Thank You

ANSWER

Which gas is responsible for holes in ozone

Posted by Keerthana Vijayan 5 years, 7 months ago

CBSE > Class 09 > Science

3 answers

Brajesh Kumar 5 years, 7 months ago

Cfc

0Thank You

Yogita Ingle 5 years, 7 months ago

Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.

1Thank You

Yash Mishra 5 years, 7 months ago

Green house gases like CO2 and Methane.

1Thank You

ANSWER

How to solve 2nd & 3rd equation of motion

Posted by Naina Choudhary. 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Abrar Khan 5 years, 7 months ago

I know

1Thank You

Fayyaz Surve 5 years, 7 months ago

By learning

2Thank You

ANSWER

How to solve physics numerecle

Posted by Akarsh Yadav 5 years, 7 months ago

CBSE > Class 09 > Science

3 answers

Yashraj Kumar 5 years, 7 months ago

Using brain

2Thank You

Anurag Yadav 5 years, 7 months ago

By using equation and formula s

1Thank You

Sakshi Jain 5 years, 7 months ago

By hand and mind

1Thank You

ANSWER

Difference between physical and chemical change ?

Posted by Naina Choudhary. 5 years, 7 months ago

CBSE > Class 09 > Science

2 answers

Anurag Yadav 5 years, 7 months ago

in which properties of an element are change is chemical and are not changed it s physical

0Thank You

Meghna Thapar 5 years, 7 months ago

Difference between physical change and chemical change: i. In a physical change, the molecules are rearranged while their actual composition remains same whereas in a chemical change, the molecular composition of a substance completely changes and a new substance is formed. ii. Physical change is easily reversible i.e original substance can be recovered whereas chemical change is irreversible i.e. original substance cannot be recovered. iii. In physical change, no new substance is formed whereas a chemical change is always accompanied by one or more new substance(s).

0Thank You

ANSWER

A running man has kE that a boy of half of his mass has . The man speed up by 1m/s and then had the boy what sre the original speed of the man and boy

Posted by Warish Murasing 5 years, 7 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

Features of ribosomes

Posted by Manindar Singh 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 7 months ago

Ribosomes are made of proteins and ribonucleic acid (RNA), in almost equal amounts. It comprises of two sections, known as subunits. The tinier subunit is the place the mRNA binds and it decodes, whereas the bigger subunit is the place the amino acids are included. It is situated in two areas of the cytoplasm. They are seen scattered in the cytoplasm and a few are connected to the endoplasmic reticulum. When they are joined to the ER they are called the rough endoplasmic reticulum. The free and the bound ribosomes are very much alike in structure and are associated with protein synthesis.

0Thank You

ANSWER

What is the male *** part

Posted by Shadow Knight 5 years, 5 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

An object is placed at the following distances from a convex lens of focal length of 15 cm: Which position of the object will produce

Posted by Amman Ansari 5 years, 7 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

What is reverberation? How can it be reduce

Posted by Warish Murasing 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Amritansh Tiwari 5 years, 7 months ago

The persistance of sound in big halls and auditorium due to the reflection of sound by floor, ceiling,walls is called reverberation.we can reduce it by the following steps: 1)panels are put on the walls to reduce reverberation. 2) carpets are spread on the floor to absorb sound. 3) heavy curtains are put on door and windows to reduce reverberation.

1Thank You

ANSWER

What are taxons?

Posted by Himanshu Kasaudhan 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 7 months ago

A taxon is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. It includes class, order, family, genus and species.

0Thank You

ANSWER

How can i find protons and neutrons in an element

Posted by Ferrari Gamer 5 years, 7 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 7 months ago

1. Mass number is the total number of neutrons and protons within the atom. 2. Atomic number is the amount of protons within the atom. 3. For neutral atoms, the electron number is the same as the atomic number. Example - Sodium (Na) Atomic number/number of protons = 11 Mass number = sum of protons and neutrons = 23 Number of neutrons = 23-11= 12 Number of protons = Number of electrons = 11 (since the sodium atom is neutral)

1Thank You

ANSWER

Tell me 3 equations of motion with every word with their full meanings for e.g type acceleration for a

Posted by Ferrari Gamer 5 years, 7 months ago

CBSE > Class 09 > Science