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

The echo is not heard any places because suppose you have in the room and speak any word but in the room you have not a single body.In the room many matter like walls, ceiling,and any more,so this matter is observe the sound.

3Thank You

ANSWER

Difference heathly and disease free

Posted by Harini Chelvan 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Shivam Yadav 7 years, 3 months ago

Healthu means that the person is behaving well in physical, mental and cope with social well being without any difficulty.

0Thank You

ANSWER

Why do you think mam ng anti vural medicine is harder than making antu bacterial medicine

Posted by Juhi Bodapati 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

What is Ratio of the cgs unit of energy to the si unit of energy?

Posted by Shreya Roy 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Shalu Bhalla 7 years, 3 months ago

An erg is the amount of the work done by a force of 1 dyne exerted for a distance of 1 cm. In cgs base unit, it is equal to 1 gcm2/s2. It is thus equal to 10 -7 joules or 100 nanojoules (nj) in SI unit

2Thank You

Mukul Kamboj 7 years, 3 months ago

1:5

2Thank You

ANSWER

Difference between JJ Thomson model and Rutherfords model of atom

Posted by Sheetal Sood 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Shivam Yadav 7 years, 3 months ago

Jj thomsan told that the positively charged particle are spread throughout in the atom whereas rutherford told that the proton lies inside the nuclues in the centre of atom

1Thank You

Abhinav Sharma 7 years, 3 months ago

JJ Thomson told that an atom is an positively charged Sphere in which negatively charged ions called electrons are embedded in it . Rutherford said that an atom consist of small positive nucleus in centre and electrons move around it. According to JJ Thomson model of an atom the positive charge and negative charge for embedded together and due to which there charges for cancelled and an Atom was converted into dump. According to rutherford's model of an atom the electrons for revolving around the nucleus which consisted of protons and neutrons but his model failed to explain electromagnetic theory.

2Thank You

Navi Sidhu 7 years, 3 months ago

JJ Thomson told that atom is a negatively charged sphere with positive ions embedded on it whereas Rutherford proved that atom consist of a small, positive nucleus in its centre

3Thank You

ANSWER

How sound is produced?

Posted by Aaaaa Aaaaa 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Shivam Yadav 7 years, 3 months ago

Sound is produced when an object vibrates

0Thank You

Akash Tiwari 7 years, 3 months ago

Sound is produced by the vibrating object

3Thank You

ANSWER

What nation was bounced from the Organisation of American States in 1962? Cuba.

Posted by Anushka Sharma 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

A bullet of mass 20 g is horizontally fired with a velocity 150m from a pistol of mass 2 kg. What is the recoil velocity of the pistol?

Posted by ? ? 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Vedant Pillai 7 years, 3 months ago

velocity= 150m/s m=20g M=2kg=2000g recoil velocity=-mv/M = -20×150/2000 = -3/2 = -1.5m/s

0Thank You

ANSWER

Give two precautions which should be taken during the experiment which shows that carbon dioxide is given out during respiration.

Posted by Mahi Khokhar 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Abhay Singh 7 years, 3 months ago

Element

0Thank You

ANSWER

Define centrifugal force

Posted by Pothees Waran 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 3 months ago

If an object moving in a circle and experiences an outward force, than this force is called as the centrifugal force. However, the force also depends on the mass of the object, the distance from the center of the circle and also the speed of rotation.
If the object has more mass, the force of the movement and the speed of the object will be greater. If the distance is far from the center of the circle the force of the movement will be more.

2Thank You

ANSWER

different between atom and ions two pointd

Posted by Pooja Singh 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 3 months ago

Atom	Ion
Smallest unit of element	Single particle or collection of particles
Takes part in chemical reaction	Cannot participate in chemical reaction
Not independent in solution	Is independent in solution
Atoms form molecule	Ions form electrovalent bond
Electrons and protons are equal	Electrons and protons are unequal
Unstable	Stable

4Thank You

ANSWER

How to get cbse guide help for two classes 9th as well as 11th

Posted by Pinki Chaudhary 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Pinki Chaudhary 7 years, 2 months ago

By going into setting

1Thank You

ANSWER

Define: 1.fiuid,2.Buoyant force

Posted by Sabita Jindal 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Pothees Waran 7 years, 3 months ago

The upward force exerted by the water on the bottle is known as buoyant force or upthrust

1Thank You

Devraj Singh 7 years, 3 months ago

Fluid is any substance which have the property to flow

1Thank You

ANSWER

what is reverberation and write method to reduce it

Posted by Soham Upadhyay 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 3 months ago

The persistence of sound in an auditorium as a result of repeated reflections of sound is called reverberation.
Ultrasounds can be used to detect cracks and flaws in metal blocks. The cracks or holes inside the metal blocks, which are invisible from outside reduce the strength of the structure. Ultrasonic waves are allowed to pass through the metal block and detectors are used to detect the transmitted waves. If there is even a small defect, the ultrasound gets reflected back indicating the presence of the flaw or defect.

0Thank You

ANSWER

Factors necessary for a person to be healthy

Posted by Sinder Singh 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 3 months ago

For a healthy person it is necessary that
The surrounding environment should be clean. Air and water-borne diseases should not spread.
personal hygiene is maintained to prevent infectious diseases.
Proper, sufficient nourishment and food is available for good immune system of our body.
Body is immunised against severe diseases

0Thank You

ANSWER

State paseal's law

Posted by Mohit Lamba 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Yogita Ingle 7 years, 3 months ago

In any fluid, the static pressure is exerted on the walls of the container and in the fluid. These forces act perpendicular to the walls of the container. When an external pressure is applied to the fluid, the pressure is distributed uniformly in all parts of the fluid and this is known as Pascal’s principle named after the Physicist Blaise Pascal.The Pascal’s principle refers to only the external pressure and within the fluid the pressure at the bottom is greater than the top.

1Thank You

Gaurav Kumar 7 years, 3 months ago

Pascal's law (also Pascal's principle or the principle of transmission of fluid-pressure) is a principle in fluid mechanics that states that pressure at a point, has infinite direction, and thus a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.

2Thank You

ANSWER

A scooter starts from rest and moves in a straight line with a constant acceleration and covers a distance of 64m in 4s.1.Calculate its acceleration and it's final velocity.2At what time the scooter had covered half the total distance?

Posted by Priyanka Bad 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

Write the formula of 'beryllium nitrate'

Posted by Riyaz Malik 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Kumar 7 years, 3 months ago

BeN2O6

1Thank You

ANSWER

Factors affecting boyunt force

Posted by ?? Mr. Jai Prakash Acharya 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 3 months ago

1-Volume of the body submerged in the liquid or volume of the liquid displaced
2-Density of the liquid
3-Acceleration due to gravity

Volume

When we push a small piece of cork into water, we experience some up thrust on our fingers. Suppose if we push a bigger piece of cork into water, we experience a greater up thrust on our fingers. Thus, it can be said that the buoyancy force increases with increase in the volume of the object.

Density

When we push a small piece of cork into water, we experience some up thrust on our fingers. Let us add some salt to the water and repeat the same experiment. It can be observed that we experience more up thrust on our fingers. With this it can be concluded that buoyancy increases with increase in density.

Acceleration due to gravity

The force of buoyancy also increases with increase in acceleration due to gravity.

4Thank You

ANSWER

Derive F=G*M*m/d*d

Posted by Dikesh Patel 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Mridul Gupta 7 years, 3 months ago

F=Gm1m2/d

0Thank You

Rajat Goswami 7 years, 3 months ago

F is directly proportional to product of mass of the bodies. _____________(1) For is inversely proportional to the square of distance between them two bodies___________(2) Combining eq.(1)&(2) and taking G (universal gravitational constant) as constant. We get : F=GMm/d² or r²

2Thank You

Queen_ Of _My _Heart 7 years, 3 months ago

Textbook me answer hoga.

1Thank You

ANSWER

A device called oscillator is used to send waves along a stretched string the string is 20 centimeter long and four complete waves fit along its length when the oscillator vibrates 30 times per second. For the waves on the string. What is their frequency

Posted by Raghuraj Yadav 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

ANSWER

Please exolain me mole concept???

Posted by Mahi Rastogi 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 7 years, 3 months ago

Mole is the measurement in chemistry. It is used to express the amount of a chemical substance.
One mole is defined as the amount of substance of a system which contains as many entities like, atoms, molecules and ions as there are atoms in 12 grams of carbon - 12".
Avogadro number:
The number of the particles present in one mole of any substance = 6.022x10²³. This is called avogadro’s number or Avogadro’s constant.
No. Of particles in 1 mole:
1 mole of hydrogen atoms represents 6.022 × 10²³ hydrogen atoms.
1 mole of hydrogen molecules represents 6.022 × 10²³hydrogen molecules.
1 mole of water molecules represents 6.022 × 10²³ water molecules.

0Thank You

ANSWER

How to find whether the substance is mixture, element or compound???

Posted by Queen_ Of _My _Heart 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Saraj Bera 7 years, 3 months ago

A compound is a pure substance composed of two or more different atoms chemically bonded to one another. A compound can be destroyed by chemical means. It might be broken down into simpler compounds, into its elements or a combination of the two. Decide whether a substance is chemically pure. If it is pure, the substance is either an element or a compound. If a substance can be separated into its elements, it is a compound. If a substance is not chemically pure, it is either a heterogeneous mixture or a homogeneous mixture.

3Thank You

ANSWER

Which of the following is pure substance? Element Compound Mixture

Posted by Deepak Yadav 7 years, 3 months ago

CBSE > Class 09 > Science

5 answers

Anjali Rawat 7 years, 3 months ago

Element is a pure susbstance

1Thank You

Muskan Kumari 7 years, 3 months ago

Element

0Thank You

Riyaz Malik 7 years, 3 months ago

Element and compounds

1Thank You

Gaurav Kumar 7 years, 3 months ago

Element and compound

1Thank You

Gungun Tyagi 7 years, 3 months ago

Element and compound

2Thank You

ANSWER

What does the Aqueous solution????

Posted by Queen_ Of _My _Heart 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Kumar 7 years, 3 months ago

An aqueous solution is a solution in which the solvent is water.

3Thank You

ANSWER

Explain any one method of crop production which ensures high yield. Please ? answer please ... This is the question of biology ?

Posted by Manisha Ranwa? 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Manisha Ranwa? 7 years, 3 months ago

Ok thanks to you both?

0Thank You

Gaurav Kumar 7 years, 3 months ago

Mixed farming is a type of farming which involves both the growing of crops as well as the raising of livestock.

1Thank You

Yogita Ingle 7 years, 3 months ago

Inter-cropping is one of the methods of crop production that ensures high yield. It is the method of growing two or more varieties of crops on the same land in a definite pattern. These crops having different nutrient requirements. Inter-cropping helps in preventing pests and diseases to spread throughout the field. It also increases soil fertility, whereas crop rotation prevents soil depletion, increases soil fertility, and reduces soil erosion.

1Thank You

ANSWER

Page 597 of 1369

myCBSEguide

myCBSEguide

Test Generator

CUET Mock Tests

Download myCBSEguide App

All Courses

Other Websites

CBSE Courses

Resources

Corporate

NCERT Solutions

CBSE Sample Papers