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Ask QuestionPosted by Shruti Agrawal 3 years, 11 months ago
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Meghna Thapar 3 years, 11 months ago
Damage to infrastructure also causes long-term impacts, such as disruptions to supplies of clean water, wastewater treatment, electricity, transport, communication, education and health care.
Measures that must be taken to prevent more flooding in the...
- Introduce better flood warning systems. ...
- Modify homes and businesses to help them withstand floods. ...
- Construct buildings above flood levels. ...
- Tackle climate change. ...
- Increase spending on flood defences. ...
- Protect wetlands and introduce plant trees strategically. ...
- Restore rivers to their natural courses. ...
- Introduce water storage areas.
Posted by Shu Kurenai 3 years, 11 months ago
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Meghna Thapar 3 years, 11 months ago
Earth's atmosphere also plays a vital role in regulating the temperature by providing a blanket of gases that not only protects us from excessive heat and harmful radiation from the sun, but also traps heat rising from the Earth's interior, keeping us warm. Influences how quickly atoms & molecules move Low temperatures cause chemicals to react slowly, which interferes with the reactions necessary for life. Life seems limited to a temperature range of minus 15oC to 115oC. In this range, liquid water can still exist under certain conditions.
Posted by Vandana Bari 3 years, 11 months ago
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Naitik Sati 3 years, 11 months ago
Yogita Ingle 3 years, 11 months ago
Newton’s First Law of Motion:
Any object remains in the state of rest or in uniform motion along a straight line, until it is compelled to change the state by applying external force.
Explanation: If any object is in the state of rest, then it will remain in rest untill a exernal force is applied to change its state. Similarly an object will remain in motion untill any exeternal force is applied over it to change its state. This means all objects resist to in changing their state. The state of any object can be changed by applying external forces only.
Posted by Bharat Kumar 3 years, 11 months ago
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Gaurav Seth 3 years, 11 months ago
Gas: Matters which have indefinite shape and volume are called gases. For example - air, oxygen, hydrogen, nitrogen, carbon-dioxide, etc.
Properties of gas
- Gas has indefinite shape
- Gas has no fixed volume.
- Gas gets the shape and volume of container.
- Gas fills the container completely.
- Gas has very low density.
- Because of low density gas are light.
- Gas can flow easily and hence are called fluid.
Posted by Jalpa Makvana 3 years, 11 months ago
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Gaurav Seth 3 years, 11 months ago
Given :
▪ Mass of block A = 1kg
▪ Mass of block B = 2kg
▪ Applied force on block A = 10N
To Find :
▪ Acceleration of the system.
▪ Magnitude of action/reaction force b/w both blocks.
Concept :
→ As per Newton's second law of motion, Ner force acting on the system is defined as the product of mass and acceleration.
→ It is a vector quantity.
→ As per Newton's third law of motion,
Reaction = -(Action )
[Note : Negative sign shows opposite direction.]
Calculation :
✴ Acceleration of the system :
✴ Action/Reaction force b/w A and B :
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Manyata Joshi 3 years, 11 months ago
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Gaurav Seth 3 years, 11 months ago
|
Distillation |
Fractional Distillation |
| Distillation is a process used to separate liquids with boiling points which comprise gaps around 50 degrees at least. | Fractional Distillation is a process used to separate liquids with closer boiling points |
| Simple distillation will have only one cycle of distillation i.e vaporization-condensation throughout the process. | The fractional distillation will have at least two cycles. |
| The experimental set up is simple. Needs a simple apparatus with two simple flasks and a condenser | The experimental set up is complex. We need a complex apparatus with a fractioning column. |
| Used in the purification of seawater | Used in crude oil refining |
Posted by Pankhuri Sharma 3 years, 11 months ago
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Gaurav Seth 3 years, 11 months ago
|
Mitosis |
Meiosis |
Interphase |
|
| Each chromosome replicates. The result is two genetically identical sister chromatids | Chromosomes not yet visible but DNA has been duplicated or replicated |
Prophase |
|
| Prophase –Each of the duplicated chromosomes appears as two identical or equal sister chromatids, The mitotic spindle begins to form. Chromosomes condense and thicken | Prophase I – crossing-over recombination – Homologous chromosomes (each consists of two sister chromatids) appear together as pairs. Tetrad is the structure that is formed. Segments of chromosomes are exchanged between non-sister chromatids at crossover points known as chiasmata (crossing-over) |
Metaphase |
|
| Metaphase -The chromosomes assemble at the equator at the metaphase plate | Metaphase I Chromosomes adjust on the metaphase plate. Chromosomes are still intact and arranged as pairs of homologues |
Anaphase |
|
| Anaphase – The spindle fibres begin to contract. This starts to pull the sister chromatids apart. At the end of anaphase, a complete set of daughter chromosomes is found each pole | Anaphase I Sister chromatids stay intact. However, homologous chromosomes drift to the opposite or reverse poles |
Posted by Haripriya Jena 3 years, 11 months ago
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Gaurav Seth 3 years, 11 months ago
Physical Changes
- The changes in which no new substance is formed are called physical changes.
- The molecular composition remains totally same.
- For example, the molecular composition of ice and water is not changed.
- The energy needed to bring a physical change is equal to the amount of energy required to reverse the change. There is no change in energy.
- The changes are reversible and temporary. The reaction gets reversed if the cause producing the change is removed. For example, water on freezing forms ice and ice on melting forms water.
- Examples of physical change
- Dissolution of sugar in water
- Melting of ice
- Freezing of water
- Boiling of water
- Melting of wax
Posted by Pankhuri Sharma 3 years, 11 months ago
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Meghna Thapar 3 years, 11 months ago
Most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells. Meiosis is the type of cell division that creates egg and sperm cells. ... During mitosis, a cell duplicates all of its contents, including its chromosomes, and splits to form two identical daughter cells. Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells. During cell division, mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus. In meiosis, prophase, metaphase, anaphase and telophase occur twice. The first round of division is special, but the second round is more like mitosis. In mitosis, prophase, metaphase, anaphase and telophase occur once. Chromosomes condense and the centrosomes begin to form an early spindle.
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Ananya K 3 years, 11 months ago
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Yogita Ingle 3 years, 11 months ago
Distance covered by the satellite in 24 hours
s=2πr
=2×3.14×42250=265464.58 km
Therefore speed of satellite,
v = distance travelled/ time taken = 265464.58/ (24×60×60) =3.07 km /s
Posted by Dêv!! Bhai!! 3 years, 11 months ago
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Dipanshu Marodia 3 years, 11 months ago
Gaurav Seth 3 years, 11 months ago
Prokaryotic cell |
Eukaryotic cell |
| Prokaryotic cells are generally small in size. | Eukaryotic cells are comparatively larger in size. |
| The nuclear material is undefined having no nuclear membrane and is called nucleoid. | Nucleus having a nuclear membrane present. |
| A single chromosome is present. | More than one chromosome is present. |
| It does not contain membrane bound cell organelle. | It contains membrane bound cell organelles like mitochondria, plastids etc. |
| Ribosome is of 70s type. | Ribosome is 80s type. |
| Cell division takes place by fission or budding or fragmentation. | Cell division takes place by mitosis and meiosis |
Posted by Imran Fareedh 4 years ago
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Nandini Ladda 3 years, 11 months ago
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Manyata Joshi 4 years ago
Manyata Joshi 4 years ago
Posted by Atharv Moyal 4 years ago
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Gaurav Seth 4 years ago
In this change a new substance is formed, hence it is a Chemical change.
Adding lemon juice changes the acidity of tea.
Tea has polyphenol pigment 7−20% and on adding lemon juice which is acidic, hydrogen ions suppress the ionization of polyphenols and that changes the colour of tea making it lighter.
Therefore, change in the colour of black tea on adding lemon juice is an example of chemical change.
Posted by Priti Tyagi 4 years ago
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Gaurav Seth 4 years ago
The initial velocity of marble is 0.4m/s.
And the retardation is 0.2m/s²,or a=-0.2m/s²
Now by first equation of motion
v=u+at
where u is initial velocity,v is final velocity a is acceleration and t is time.
Putting the values in the equation,we get
0=0.4+(-0.2)t. (final velocity is 0 because body comes to rest.)
or,0.2t=0.4
or,t=0.4/0.2=2s
Posted by Shevani 123 4 years ago
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Gaurav Seth 4 years ago
Carbon and oxygen reacts in a ratio 3:8 by mass to form Carbon dioxide
Hence the required reaction is ;
C + O2 --> CO2
Carbon : Oxygen = 3 : 8
Due to law of constant proportion, the mass ratio in which the reactants will react will remain constant.
Carbon --> 9 g
Oxygen --> ?
C : O2 = 3:8
9 : O2 = 3:8
9/O2 = 3/8
Mass of oxygen required
= (9/3)×8
= 3×8
= 24 g
Posted by Prateek Paital 4 years ago
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Gaurav Seth 3 years, 11 months ago
Stages of Mitosis
Right before prophase, the cell spends most of its life in the interphase, where preparations are made before the beginning of mitosis (the DNA is copied). However, since the actual process involves the division of the nucleus, prophase is technically the first stage of this process.
The different stages of mitosis occurring during celldivision are given as follows-
Interphase
Before entering mitosis, a cell spends a period of its growth under interphase. It undergoes the following phases when in interphase:
Prophase
Prophase immediately follows S and G2 phase of the cycle and is marked by condensation of the genetic material to form compact mitotic chromosomes composed of two chromatids attached at the centromere.
The completion of prophase is characterised by the initiation of the assembly of the mitotic spindle, the microtubules, and the proteinaceous components of cytoplasm that help in the process.
The nuclear envelope starts disintegrating.
Prometaphase
In the prometaphase, the nuclear envelop disintegrates. Now the microtubules are allowed to extend from the centromere to the chromosome. The microtubules attach to the kinetochores which allow the cell to move the chromosome around.
Metaphase
At this stage, the microtubules start pulling the chromosomes with equal force, and the chromosome ends up in the middle of the cell. This region is known as the metaphase plate. Thus, each cell gets an entire functioning genome.
Anaphase
The splitting of the sister chromatids marks the onset of anaphase. These sister chromatids become the chromosome of the daughter nuclei. The chromosomes are then pulled towards the pole by the fibres attached to the kinetochores of each chromosome. The centromere of each chromosome leads at the edge while the arms trail behind it.
Telophase
The chromosomes that cluster at the two poles start coalescing into an undifferentiated mass, as the nuclear envelope starts forming around it. The nucleolus, Golgi bodies and ER complex, which had disappeared after prophase start to reappear.
Telophase
Telophase is followed by cytokinesis, which denotes the division of the cytoplasm to form two daughter cells. Thus, it marks the completion of cell division.
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