CBSE > Class 10 > Science | CBSE Board | Homework Help

The inside of a car with its windows closed is hotter than outside due to green house effect as the glass in the windows absorb infrared radiations of the sun but do not allow them to escape or reflect back, thus increasing the temperature of the car on the inside.

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What is Atomic mass?

Posted by Ravi . 4 years, 9 months ago

CBSE > Class 10 > Science

4 answers

Simmi Fagna 4 years, 9 months ago

The mass of an atom of a particular chemical substance.

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Anil Sah 4 years, 9 months ago

Sum of masses of the proton and neuron of the atom

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Khushi Baliyan 4 years, 9 months ago

Total mass of any atom is its atomic mass

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Neel Menghani 4 years, 9 months ago

Atomic mass can be defined as the total mass of one atom of any given element.

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Defination of base

Posted by Ishika Shrama 4 years, 9 months ago

CBSE > Class 10 > Science

4 answers

Prateeek Chauhan 4 years, 9 months ago

Base are the substances which dissociates in water to produce hydroxide hydroxide ions.

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Ravinder Yadav 4 years, 9 months ago

Base are those substance that gives oH- ion in aqueous solutions

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Sahil Giri 4 years, 9 months ago

Base are bitter in taste.it is good conductor of heat and electricity. Bases highly soluble in water like alkalis.it is soapy in texture

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Adithya Dev A 4 years, 9 months ago

According to Arrhenius, BASES are substances which furnish OH^- (aq) ions when in aqueous solutions. They are colourless and odourless substances which are bitter in taste and are slippery and soapy in texture. They are good conductors of electricity and they are highly corrosive. Bases highly soluble in water are ALKALIS. Eg:- NaOH, KOH, etc. Bases which are partially soluble in water are called WEAK bases. Eg:- Zn(OH)2, Ca(OH)2, Al(OH)3, etc.

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What is the effect of dna copying which is not perfectly accurate on the reproductioyn processes?

Posted by Anuj Bhardwaj 4 years, 9 months ago

CBSE > Class 10 > Science

2 answers

Harsh Janghu 4 years, 9 months ago

VARIATIONS. Which are imp for evolution of any species (i.e. very slow process)

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Adithya Dev A 4 years, 9 months ago

It would lead to formation of VARIATIONS. If these variations go hand in hand with the constantly changing environment, they enhance survival rate of a species.

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What is the effect of dna copying which is not perfectly accurate on the reproduction processes?

Posted by Anuj Bhardwaj 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Siddharth Sarda 4 years, 9 months ago

The DNA copying which is not perfectly accurate in the reproduction process results in variations in populations for the survival of species. If the variation are more drastic then the DNA will not be able to function properly leading to the death of the cell.

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In a redox reaction A+B it will form B²+A² identify the oxidising agent and the substance which is oxidised

Posted by Diksha Devi 4 years, 9 months ago

CBSE > Class 10 > Science

0 answers

ANSWER

A concave mirror produces 10cm long image of an object of height of 2cm.what is the magnification produced

Posted by அருண் பிரசாத் 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Adithya Dev A 4 years, 9 months ago

Is it real or virtual? If real, m = -10/2 = -5 and if virtual, m = 10/2 = +5.

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an object 1m tall in front of convex lens

Posted by The Girl Suhani Jain 4 years, 9 months ago

CBSE > Class 10 > Science

0 answers

ANSWER

student draws a schematic diagram of a circuit consisting of a battery of two cells of 1.5 V each, three resistors having 2 2, 3 2 and 5 2, an ammeter, a voltmeter, a plug key all connected in series. Study it and find out the mistakes in the circuit and redraw the correct circuit.

Posted by A. Kumaaran 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Adithya Dev A 4 years, 9 months ago

Where is the circuit.

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How can genetic inheritance determine ***?

Posted by #Manish Singh 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Khushi Baliyan 4 years, 9 months ago

By looking the character of the person

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If the alveolar surface were spread out,it would cover about 80m^2.how much do you think the surface area of your body is. Consider how efficient exchange of gases becomes because of the large surface available for the exchange to take place

Posted by #Manish Singh 4 years, 9 months ago

CBSE > Class 10 > Science

0 answers

ANSWER

Give reason why do chips manufacturers usually flush bags of chips with gas such as nitrogen???

Posted by Sheena Gurung 4 years, 9 months ago

CBSE > Class 10 > Science

4 answers

Adithya Dev A 4 years, 9 months ago

Nitrogen gas is INERT or UNREACTIVE in nature. This would prevent the chips from undergoing RANCIDITY ie, oxidation of FATS and OIL.

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Khushi Baliyan 4 years, 9 months ago

Because nitrogen gas prevent the chips from getting oxidised?

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#Manish Singh 4 years, 9 months ago

To prevent the chips from getting oxidised

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Akhya Sahay 4 years, 9 months ago

To prevent it from rancidity

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Veins are thin walled and have value .justify

Posted by Shees Turab 4 years, 9 months ago

CBSE > Class 10 > Science

5 answers

Ravinder Yadav 4 years, 9 months ago

Veins have thin wall because blood don,t flow with high pressure in veins

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Adithya Dev A 4 years, 9 months ago

A note : the "them" given after "back to" is the cells. Sorry.

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Adithya Dev A 4 years, 9 months ago

Veins do not receive blood directly from heart. So, it does not have to withstand the pressure from heart. So, its walls are THIN in nature. Since it does not receive blood directly from heart, no pressure is added to the DEOXYGENATED blood flowing through veins. So, to prevent BACKFLOW of this blood back to them and further damage to cells, veins have VALVES.

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Shivam Dabas 4 years, 9 months ago

Veins are thin walled because there is low blood pressure in them and to prevent the backflow of blood, they have valves.

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Vansh Gupta 4 years, 9 months ago

Veins have thin walls because the blood there is no longer under pressure and they have valves to ensure blood flow in one direction.

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How the voltmeter is connected in a circuit

Posted by Saurabh Pandey 4 years, 9 months ago

CBSE > Class 10 > Science

5 answers

Adithya Dev A 4 years, 9 months ago

A voltmeter is connected in PARALLELS across the points between which POTENTIAL DIFFERENCE has to be measured.

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Khushi Baliyan 4 years, 9 months ago

Connecting in parallel

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Shivam Dabas 4 years, 9 months ago

Parallel combination with resistor

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Akhya Sahay 4 years, 9 months ago

It is connected in parallel

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Vansh Gupta 4 years, 9 months ago

In parallel

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What is the sign of angle of deviasion

Posted by Babita Mohanta 4 years, 9 months ago

CBSE > Class 10 > Science

2 answers

Akhya Sahay 4 years, 9 months ago

Angle of deviation is represented by the letter 'd'

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E.Shivani Nair 4 years, 9 months ago

It is represented by letter D

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How is the refractive index of a medium related to the speed of light? Obtain an expression for refractive index of a medium with respect to another in terms of speed of light in these two media?

Posted by Aasim Ahmed 4 years, 9 months ago

CBSE > Class 10 > Science

2 answers

Adithya Dev A 4 years, 9 months ago

n=c/v. (where n is refractive index, c is speed of light in vacuum ie, 3*10^8 m/s and v is speed of light in the medium.) Relative refractive index => n12=n1/n2=v2/v1 and n21=n2/n1=v1/v2.

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Akhya Sahay 4 years, 9 months ago

Refractive index = speed of light in medium 1/speed of light in medium 2

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What do you think will be the impact of these on our environment?

Posted by #Manish Singh 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Aasim Ahmed 4 years, 9 months ago

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water.

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What is phenomenon

Posted by Nawabzada Naved 4 years, 9 months ago

CBSE > Class 10 > Science

2 answers

Khushi Baliyan 4 years, 9 months ago

Process

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Suraj Gupta 4 years, 9 months ago

Process is known as phenomenon

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Ph value of dil.NaoH

Posted by Anshuman Singh 4 years, 9 months ago

CBSE > Class 10 > Science

3 answers

Khushi Baliyan 4 years, 9 months ago

Ph 14

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Akhya Sahay 4 years, 9 months ago

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E.Shivani Nair 4 years, 9 months ago

Almost 14pH

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A mirror forms an image on the screen with double the size of the object. What is the image distance?(focal length of the mirror is 60 cm)

Posted by Shilpa Panchal 4 years, 9 months ago

CBSE > Class 10 > Science

1 answers

Aryan Chahal 4 years, 9 months ago

120cm on same side of mirror

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Why do veins have valves?

Posted by Sakshi . 4 years, 9 months ago

CBSE > Class 10 > Science

4 answers

Suraj Gupta 4 years, 9 months ago

To prevent back flow of blood and allow the blood to flow only in one direction

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Malaika Sharma 4 years, 9 months ago

In veins blood flows under low pressure.To prevent back flow of blood, veins have valves.

3Thank You

Raj Tiwari 4 years, 9 months ago

Because the blood flows from the veins under very high pressure to transport from one part to other..

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Shilpa Panchal 4 years, 9 months ago

They have to face..

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ANSWER

Balance the chemical equation Fe+H20 == fe304+h2

Posted by Bindas Gamer 4 years, 9 months ago

CBSE > Class 10 > Science

4 answers

Akhya Sahay 4 years, 9 months ago

3Fe +4h2o=Fe3o4+4h2

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Babita Mohanta 4 years, 9 months ago

3Fe+ 4H2O → Fe3O4 +4H2 prolong

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Deepika Sihag 4 years, 9 months ago

3Fe+4H2O===Fe3O4+4H2

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Annanya Gupta 4 years, 9 months ago

3Fe+4H2O=Fe3O4+4H2

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ANSWER

Why sodiam metal kept in kerosene

Posted by Bindas Gamer 4 years, 9 months ago

CBSE > Class 10 > Science

5 answers

Adithya Dev A 4 years, 9 months ago

Metals like SODIUM and POTASSIUM are highly REACTIVE in nature. So, when left open in air, it reacts so vigorously that it may even catch fire. So, to prevent accidental fires and emergencies, it is kept immersed in KEROSENE oil.

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Harshal Joshi 4 years, 9 months ago

It catches fire in open air, so it is kept in kerosene oil

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Malaika Sharma 4 years, 9 months ago

Sodium is highly reactive metal. It reacts vigrously when kept in open and catches fire.So it is kept in kerosene.

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Bhoomika Maheshwari 4 years, 9 months ago

As per your query,, Sodium is a very reactive metal .if kept in air it can catch fire by react ing with oxygen present in air ..and by immersing in kerosene it would prevent from reaction . Thank you .

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Annanya Gupta 4 years, 9 months ago

Sodium is a very highly reactive metal that acts vigorously with oxygen, carbon dioxide and moisture which may even catch fire. So, to prevent this explosive reaction Sodium metal is immersed in Kerosene because it do not react with Kerosene. Hope this helps you!.....

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A man with blood group A marries with a woman with blood group O and their daughter has blood group O. Is this information enough to tell which of the trait blood group A or O - is dominant? Why or why not?

Posted by Harshal Joshi 4 years, 9 months ago

CBSE > Class 10 > Science

3 answers

Tanya Chauhan 4 years, 9 months ago

Yes it's enough to tell which of the trait blood group is dominant here blood group O is dominant because the progeny is of blood group O

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Adithya Dev A 4 years, 9 months ago

O is the DOMINANT trait as it has successfully been able to suppress the A blood group. It is enough as there exists a chance that this is F1 progeny, my friend.

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Akash Jangid 4 years, 9 months ago

It's not enough because only with a single crossover it can't be identified It have 4 out comes and to know the dominant trait we will have to study the complete crossover and it's outcomes.

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Assertion reason type questions : 1). Assertion:Diamond is a conductor of electricity and heat Reason: Diamond is soluble in all known solvents.

Posted by Harshal Joshi 4 years, 9 months ago

CBSE > Class 10 > Science

3 answers

Akhya Sahay 4 years, 9 months ago

Both are incorrect

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Ayushi Verma 4 years, 9 months ago

Assertion and reason are incorrect

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Akshat Sachdeva 4 years, 9 months ago

A and R are incorrect

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Assertion reason type questions: 1). Assertion: The transmission of characters from the parents to their offspring is called heredity Reason: There are two types of genes namely dominant genes and recessive genes.?

Posted by Harshal Joshi 4 years, 9 months ago

CBSE > Class 10 > Science

3 answers

Adithya Dev A 4 years, 9 months ago

Both assertion and reason are true but reason is not the correct explanation for assertion.

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Akhya Sahay 4 years, 9 months ago

Assertion is correct reason is not correct.

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Akshat Sachdeva 4 years, 9 months ago

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If the charge on an electron is 1.6x10^-19 C find the approximate number of electrons in 1C?

Posted by Harshal Joshi 4 years, 9 months ago

CBSE > Class 10 > Science

2 answers

Annanya Gupta 4 years, 9 months ago

Solution:– Charge on one electron=1.6×10^-19 C Amount of charge (Q)=1 C No. Of electron=? Let the no. Of electron be=n Q=n×e- 1=n×1.6×10^-19 1÷1.6×10^-19=n 0.625×10^19=n So, the no. Of electron=0.625×10^19 Hope this helps you!.....

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Bindas Gamer 4 years, 9 months ago

Given charge -1 Electron-1.6×10^-19 Formula q-n×e And solve it

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