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

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

Ask Question

What is density ?

Posted by Ankit Mishra 5 years, 3 months ago

3 answers

Johnson Gi 5 years, 3 months ago

Density is the mass of a substance per unit of volume. It is used to measure the compactness of a substance, and is commonly expressed in g/cm³, or lb/ft³. The density of a sample is expressed with the Greek letter "ρ" (the Latin letter D can also be used) and is calculated as: ρ = m / v For example, if you fill 500cm³ of a sample into a glass beaker, and the mass weighs 1000g, then the density would be: ρ = 1000g/500cm³ = 2g/cm³

1Thank You

Muskan Thakur 5 years, 3 months ago

The mass per unit volume of a substance it's called density.

1Thank You

Yogita Ingle 5 years, 3 months ago

The density of material shows the denseness of that material in a specific given area. A material’s density is defined as its mass per unit volume. Density is essentially a measurement of how tightly matter is packed together. It is a unique physical property for a particular object. The principle of density was discovered by the Greek scientist Archimedes. It is easy to calculate density if you know the formula and understand its related units.

0Thank You

ANSWER

Osmosis is a special kind of diffusion in short

Posted by Khachuk Kumar Debbarma 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Kumar Kancharla 5 years, 3 months ago

Mass/volume

0Thank You

Yogita Ingle 5 years, 3 months ago

Diffusion is the process in which molecules of a substance move from the place of their higher concentration to the place of their lower concentration (no membrane is required). But during osmosis, the solvent (water) molecules move from the place of their higher concentration to the place of their lower concentration through a semi-permeable membrane. Thus, osmosis is termed as a special kind of diffusion.

0Thank You

ANSWER

Whar is a solution

Posted by Botta Sushma 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Muskan Thakur 5 years, 3 months ago

Solution is a homogeneous mixture of two or more substances.

0Thank You

Amit Amit 5 years, 3 months ago

A Solution is a homogeneous mixture of two or more substances. E.g.,nimboo pani, soda water

0Thank You

ANSWER

Give reasons for the following observation the smell of hot sizzling food reaches you several metres away but to get the smell from cold food you have to go close

Posted by Rashi Marathe 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Bhumika ? 5 years, 3 months ago

Because hot food has high kinetic energy

0Thank You

Muskan Thakur 5 years, 3 months ago

Solid diffuse at a very slow rate.if the temperature of solid particles is increasing Into air in increasing. So, the kinetic energy increasing.

0Thank You

ANSWER

what is the golgi apparatus

Posted by Banti Singh 5 years, 3 months ago

CBSE > Class 09 > Science

4 answers

Keshar Pundir Rana 5 years, 3 months ago

Xxxx???

0Thank You

Keshar Pundir Rana 5 years, 3 months ago

Golgi aaperatus has a function of storge modifications and packaging of the material

0Thank You

Ekta Ekta 5 years, 3 months ago

It is found in eukaryotic cell and helps in package of protein into vesicles

0Thank You

Tanisha Sharma 5 years, 3 months ago

The golgi apparatus; also knows as the golgi complex: golgi body ; or simply the golgi ; is an organcell found in most eukaryotic cells : part of the endomembrance syestm in the cytoplasm ; it packages proteins into membranes bound vesicles inside the cell before the vesicles are sent to their destinations ?

2Thank You

ANSWER

Matter in our surrounding chapter explanation

Posted by Sanvi Tamang Sanvi Tamang 5 years, 3 months ago

CBSE > Class 09 > Science

5 answers

Keshar Pundir Rana 5 years, 3 months ago

?????

0Thank You

Keshar Pundir Rana 5 years, 3 months ago

Everything is matter

0Thank You

Bhumika ? 5 years, 3 months ago

Earlier ,it was beleived that the matter was made of panchtatav- water,fire,earth,sky,air

1Thank You

Bhumika ? 5 years, 3 months ago

All of the things around us which have mass is called matter

1Thank You

Bhumika ? 5 years, 3 months ago

Anything which occupies space and has mass is called matter

2Thank You

ANSWER

Maximum movement of particles

Posted by Amisha Rani 5 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Bhumika ? 5 years, 3 months ago

Maximum movement of particles is in gas because thay have high kinetic energy

0Thank You

Keshar Pundir Rana 5 years, 3 months ago

Maximum partical movement in solid ?

0Thank You

Amit Amit 5 years, 3 months ago

Maximum movement of particles are in gases

0Thank You

ANSWER

Explain the process of chromatography

Posted by Poonam Jain 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 3 months ago

Chromatography is the technique used for separation of those solutes that dissolve in the same solvent.
To understand how this technique can be used let us perform an activity.
Take a thin strip of filter paper. Draw a line on it using a pencil, approximately 3 cm above the lower edge as shown in figure(a). Put a small drop of ink (water soluble, that is, from a sketch pen or fountain pen) at the centre of the line. Let it dry. Lower the filter paper into a jar/glass/ beaker/test tube containing water so that the drop of ink on the paper is just above the water level, as shown in Fig(b) and leave it undisturbed.

0Thank You

ANSWER

Name the smallest cell and the longest cell in human body??

Posted by Anushka ?? Singh 5 years, 3 months ago

CBSE > Class 09 > Science

4 answers

Keshar Pundir Rana 5 years, 3 months ago

Sperm?‍??‍??‍??‍??‍??‍???

0Thank You

Rahul Sharma 5 years, 3 months ago

Smallest cell WBC and largest nerve cell (neuron)

0Thank You

Kunal Drall 5 years, 3 months ago

Longest cell is nerve cell and smallest cell is sperm cell

0Thank You

Daniel Thomas 5 years, 3 months ago

The smallet cell is the sperm cell and the longest cell is neuron or the nerve cell.

1Thank You

ANSWER

Rubber can change it's shape but it's a solid

Posted by Muskan Thakur 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Rahul Sharma 5 years, 3 months ago

Because of its flexibility

0Thank You

ANSWER

How do we liquefy the gases?

Posted by Rajesh Kumar 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Bhumika ? 5 years, 3 months ago

By applying high pressure or decreasing the temperature

1Thank You

Muskan Thakur 5 years, 3 months ago

Gases can be liquified by the increasing the pressure and decreasing the temperature because the particles are closed and gases can be liquified

1Thank You

ANSWER

What is said to be the "kitchen of a plant cell" ?

Posted by Aryavi Kumari 5 years, 3 months ago

CBSE > Class 09 > Science

5 answers

Ekta Ekta 5 years, 3 months ago

Chlorophyll

0Thank You

Rahul Sharma 5 years, 3 months ago

Generally plastids are called kitchen of the cell.

0Thank You

Haresh Shiva 5 years, 3 months ago

Chloroplast

0Thank You

Roshini Kumar 5 years, 3 months ago

chloroplast

0Thank You

Jenisha Joye 5 years, 3 months ago

ANSWER :Chloroplast REASON :It contains chlorophyll which is helps to prepare food by the plant of its own

0Thank You

ANSWER

Why human blood is red

Posted by Rajeev Kumar 5 years, 3 months ago

CBSE > Class 09 > Science

5 answers

Ekta Ekta 5 years, 3 months ago

Because of presence of hemoglobin

1Thank You

Kunal Drall 5 years, 3 months ago

Due to hemoglobin

1Thank You

Jayati Thukral 5 years, 3 months ago

Haemoglobin gives the blood a red colour

1Thank You

Suhani Singh 5 years, 3 months ago

Due to hemoglobin

1Thank You

Ayushi Menon 5 years, 3 months ago

Because It contains Hemoglobin.

1Thank You

ANSWER

What are the different states in which water is found during the water cycle

Posted by Aakarsh Karol 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 3 months ago

The different states in water is found in the water cycle are solid state , liquid state and gaseous state..
1. Water occurs in the form of water vapour in the gaseous state. It evaporates from the surface of water bodies and mixes with air(evaporation).
2. Water vapour condenses high up in the atmosphere and falls on the earth in the form of rain in liquid state( condensation).
3. In Solid state water is formed by the freezing of liquid droplets in upper layer of atmosphere these droplets fall on the earth in the form of Snow hail and sleet ( called precipitation).

0Thank You

ANSWER

Why proton is not removed during the formation of anion???????

Posted by Suhani Singh 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 2 months ago

When an ion is formed, the number of protons does not change. Neutral atoms can be turned into positively charged ions by removing one or more electrons. ... Atoms that gain extra electrons become negatively charged. A neutral chlorine atom, for example, contains 17 protons and 17 electrons. An anion is an ion that carries a negative charge, causing it to migrate to the anode (positive electrode) in electrolysis. It has more electrons than protons, resulting in the negative charge.

1Thank You

ANSWER

Where is vibranium metal found

Posted by Hæçķəŕ 894 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 2 months ago

In the Marvel Universe, vibranium is a rare material found in Wakanda, home of King T'Challa (aka Black Panther). Vibranium's unique properties have enabled Wakanda to become an unrivaled technological powerhouse. Vibranium is a real metal found only in the fictional country of Wakanda. So it's real, but only if you live in a world that contains a country in Africa called Wakanda that everyone assumes is a backwards third world country but is, in fact, a technological Marvel. ... Wakandan Vibranium is considered to be the standard.

0Thank You

ANSWER

What do you mean by friction

Posted by Joban Bhangu 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Aadarsh Chowdhary 5 years, 3 months ago

Friction is a force that holds back the movement of a sliding object.

1Thank You

Preeti Sharma 5 years, 3 months ago

Friction is the force which help us to move easily because if we apply same amount of force as friction then we move easily

1Thank You

ANSWER

What is tyndall effect , write about dispersed phase and dispersing medium giving example s of colloid

Posted by Ajay Chaurasiya 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 2 months ago

Tyndall effect can be defined as the scattering of a beam of light by colloidal particles present in a colloidal solution. This effect can be observed when a fine beam of light passes through a small hole in a dark room. This effect occurs due to the scattering of light by particles of dust or smoke present in the air. The Tyndall effect can also be observed when sunlight passes through the canopy of a dense forest. In the forest, the mist contains tiny droplets of water which act as colloidal particles dispersed in the air.

0Thank You

ANSWER

What does inertia means?

Posted by Jayati Thukral 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Preeti Sharma 5 years, 3 months ago

Inertia is that property of a body due to which it resists a change in its state of rest or of uniform motion Inertia of a body depends on its mass

1Thank You

Yogita Ingle 5 years, 3 months ago

Inertia is the natural tendency of an object to resist a change in its state of motion or of rest.
The mass of an object is a measure of its inertia.
A force that is just enough to cause a small cart to pick up a large velocity will produce a negligible change in the motion of a train, because of train’s large inertia.

2Thank You

ANSWER

A car travel 30 km at a uniform speed of 40 km/h and the next 30 km at a uniform speed of 20 km/h. Find its average speed

Posted by Anshika Kumari 5 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Aadarsh Chowdhary 5 years, 3 months ago

We know that, Speed=Distance / time .°. Time =dist / speed Let's see the first case, s = distance = 30 km v = speed = 40 km/hr t = time = 30 / 40 =3/4 hrs Let's see the second case, s = 30 km v = 20 km/hr t = 30 / 20 t = 3/2 hrs Avg. Speed =Total distance/ Total time =(30 + 30) / (3/4) + (3/2) =60 / ( 3 + 6 ) /4 =60 / 9 × 4 =20 / 3 × 4 =80 / 3 =26.67 ( Approx. ) Hence, Average speed of the car is 26.67 km/hrs ( Approx).

1Thank You

Yogita Ingle 5 years, 3 months ago

Given that ,
    1st 30 km uniform speed is (u1) = 40 km/h
     2nd 30 km uniform speed is ( u2 ) = 20 km/h
     total distance ( d ) = 30 + 30 = 60 km
     time taken in 1st time = d / t = 30/40 also, 3h / 4 = 180/4 = 45 min
     time taken in 2nd time = d/t = 30/20 also, 3h/2 = 180/2 = 90 min
    total time = 45 + 90 = 135 min = 135/60 h
average speed = 60/135/60 = 60 * 60 /135 = 26.66 km/h

0Thank You

Prithviraj Talikoti 5 years, 3 months ago

The average speed of car is 26.67km/h

1Thank You

ANSWER

What are AIDS

Posted by Prithviraj Talikoti 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 3 months ago

AIDS i.e. Acquired immune deficiency syndrome, is the final stage of HIV disease, which causes severe damage to the immune system. Human immunodeficiency virus (HIV) causes AIDS.

The virus attacks the immune system and leaves the body vulnerable to a variety of life-threatening infections and cancers. Common pathogens that usually do not cause serious disease in people with healthy immune systems can cause fatal illnesses in people with AIDS.
The virus can be spread (transmitted) through sexual contact, through blood transfusions or needle sharing, from infected pregnant mother to child or from a nursing mother to her baby through her breast milk. Blood, semen, vaginal secretions, and breast milk have been shown to transmit this infection to others.

2Thank You

ANSWER

Is matter continues

Posted by Rohan Mishra 5 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Jayati Thukral 5 years, 3 months ago

No, matter is particulate in nature

0Thank You

Muskan Thakur 5 years, 3 months ago

Yes

0Thank You

Sneha Kashyap 5 years, 3 months ago

What are the characteristics of particles of matter .

2Thank You

ANSWER

Name the Organelles present in the liver of animal for detoxification

Posted by Shriraj Kadam 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Preeti Sharma 5 years, 3 months ago

Smooth endoplasmic reticulum

1Thank You

ANSWER

Draw velocitu-time grafh of a stone theown bertically upwards and then coming downwards after attainly the maximum height?

Posted by Aparna Singh 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 3 months ago

Let the initial velocity=u m/s
Let ' t' be the time taken to reach the maximum height h.
At maximum height, velocity becomes zero and the ball starts it's backward journey .
Here in the graph, we can see that velocity in backward journey increases but in negative direction till the stone reaches to ground.
Please refer the attachment for velocity time graph.

0Thank You

ANSWER

Give an example of a reaction where following involves

Posted by Nallasivan Nallasivan 5 years, 3 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

What is electromegnatic microscope?explain with diagram

Posted by Devashish Pandit ??? 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Aadarsh Chowdhary 5 years, 3 months ago

An Electromagnetic microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. Electromagnetic microscopes are used to investigate the ultrastructure of the wide range of biological and inorganic specimens including microorganisms cells large molecules etc.

0Thank You

ANSWER

What do you mean by magnitude of displacement . Explain

Posted by Aparna Singh 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Aadarsh Chowdhary 5 years, 3 months ago

Magnitude of displacement is technical way of saying distance as measured directly between the starting point and endpoint

0Thank You

Yogita Ingle 5 years, 3 months ago

The magnitude of dispalcement of a particle in motion for a given time is the shortest distance between the initial and final position of the particle in that time.
The magnitude is always less than or equal to the distance travelled by an object.That is total path length is greater than the magnitude of displacement.
If the motion of the particle is in one dimension i.e., along along a straight line, then the magnitude of displacement is equal to the total path lenght travelled by the object in the given time.

0Thank You

ANSWER

on boiling potato and then put it in the hypotonic solution it does not swell up why give reasons

Posted by Abhinav Gupta 5 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Bhavya Singh 5 years, 3 months ago

Because when the cell of potato get boiled,its cells become dead.So the process of osmosis stop in dead cell

0Thank You

Ashwini Singh Rathore 5 years, 3 months ago

When a potato is boiled, its cells die and thus do not support osmosis.

1Thank You

ANSWER

A train starting from a railway station And moving with uniform acceleration attains a speed 40km/h in 10mins.Find its acceleration.

Posted by Aparna Singh 5 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 3 months ago

Initial speed of the train, u = 0 km (Because train starts from the rest.

Final speed of the train, v = 40 km/h = \frac{5}{18} × 40 = 11.11 m/s.

Time taken to attain the speed = 10 minutes = 10 × 60 = 600 sec.

Acceleration of the train.

$⇒ a=\frac{v-u}{t}$

Putting all the values, we get

$⇒ a=\frac{v-u}{t}$

$⇒ a=\frac{11.11-0}{600}$

$⇒ a=\frac{11.11}{600}$

$⇒ a=0.0185 \: m/s^2$

Hence, Acceleration of the train is 0.0185 m/s².

0Thank You

ANSWER

What is chloroplast, chromosomes , golgi apparatus , mitochondria, plant cell and animal cell?

Posted by Soham Basu 5 years, 3 months ago

CBSE > Class 09 > Science

4 answers

Soham Basu 5 years, 2 months ago

Thank you Ritik Varshney

1Thank You

Muskan Thakur 5 years, 3 months ago

Green colors plastids it's called chloroplasts

1Thank You

Ritik Varshney 5 years, 3 months ago

Chloroplast-it is a type of plastid. They are green in colour and help in process of photosynthesis ,so it is also called kitchen of the cell. Chromosome-these are thread like or rod like structure which form chromatin material. It helps in gene information. Golgi apparatus-it was discovered by camilo golgi. It consists of stacks of membrane bound vesicles that function is a storage ,modification. Mitochondria-it was discovered by Albert von kollikar. It is an organelle found in large numbers in most cell, in which the biochemical processes of respiration energy production occur.so, it is called powerhouse of the cell. Plant cell- in plant cell cell wall and plastid is present, vacuoles are very big in size, plasma membrane also present and the nucleus lie in one side of a cell. Animal cell-in animal cell cell wall and plastid is absent, vacuoles are small in size, plasma membrane is absent and nucleus lies in centre of the cell.

2Thank You

Soham Basu 5 years, 3 months ago

Please help to solve this questions

2Thank You

ANSWER