Ask questions which are clear, concise and easy to understand.
Ask QuestionPosted by Supriya Mishra 5 years, 1 month ago
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Posted by Meraj Alam 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
(a) (i) Between F and 2F of a lens.
(ii) Within the focal length.
© No effect on focal length, but intensity decreases.
Posted by Maahi Chawla 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Transition elements
- The elements belonging to groups 3 to 12 are transition elements.
- In these elements last electron enters (n-1)d subshell.
- The properties of these elements are intermediate between s-block and p-blck elements.
- These elements represents change or transition in properties from most electropositive to least electropositive elements.Therefore these elements are called transition elements.
Examples
The most common metals used in construction and manufacturing(iron), metals used in coins(nickel, copper) and metals used in modern technology(titanium)
Posted by King Adithya H M... 5 years, 1 month ago
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Unique Dragons 5 years, 1 month ago
Posted by Nihalahmed Aminsab Gachinmahal 5 years, 1 month ago
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Satyam Rai 5 years, 1 month ago
King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Caustic soda is an alkali salt which is also called Lye. It is the common name of sodium hydroxide.
Sodium hydroxide can be prepared by various methods like:
- Castner-Kellner process
- Nelson Diaphragm cell
- Loewig’s process
Caustic Soda Uses
- It is used as a cleansing agent and in the manufacturing of washing soda.
- Sometimes, sodium hydroxide is also used as a reagent in the laboratories.
- It is used in the preparation of soda lime.
- It is used in the extraction of aluminium by purifying bauxite.
Posted by Maahi Chawla 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Achievements of Mendeléev’s periodic table
- element with a slightly greater atomic mass were placed
before an element with a slightly lower atomic mass with an inverted sequence so as to group the elements with similar properties. For example, cobalt with atomic mass 58.9 was placed before nickel with atomic mass 58.7. - He left some gaps in the Periodic Table with the prediction of
existence of some elements that were not discovered at that time. - He named the future elements by prefixing a Sanskrit numeral, Eka (one) to the name of preceding element in the same group.
- For instance, scandium, gallium and germanium, discovered later, have properties
similar to Eka–boron, Eka–aluminium and Eka–silicon, respectively. - Noble gases like helium (He), neon (Ne) and argon (Ar) were discovered
later as they are present in exceptionally low concentrations in the atmosphere due to their inertness.
Limitations of Mendeléev’s classification
- No fixed position could be assigned to hydrogen in the Periodic Table.
- Isotopes discovered long after Mendeléev periodic classification of
elements imparted a challenge to Mendeleev’s Periodic Law. - The atomic masses of elements did not increase in a steady manner while going from one element to other which made it difficult to predict the number of elements that could be discovered between two elements.
Posted by Nusrat Kadiwala 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
Ohm’s law : When the physical conditions such as temperature etc. remain same, the current flowing through the conductor is directly proportional to the potential difference applied across the ends of the conductor, i.e.,
I ∝ V or V ∝ I
⇒ V/I = constant
⇒ V = IR
Where R is constant of proportionality and is called resistance of the wire.
Necessary condition for validity of Ohm’s law is that physical condition such as temperature of the conductor remains same.
Procedure: Experiment to verify ohm's law
Procedure : 1. Connect the various components as.
2. Close the sky, so that current begins to flow in the circuit.
3. Note down the potential difference (V) across the conductor PQ of resistance R shown by the voltmeter and the corresponding current (I) shown by the ammeter.
4. Now move the knob of rheostat so that the current in the circuit increases.
5. Again note down the potential difference (V) across the conductor R in the voltmeter and current in the circuit shown by ammeter.
6. Repeat the experiment five times by increasing the current in the circuit by moving the knob of the rheostat in steps.
| S. No. | Potential Difference (V) | Current (I) | V/ I |
| 1 | |||
| 2 | |||
| 3 | |||
| 4 |
The value of V/I = R (constant) Plot a graph between V and I by taking V along X- axis along. We get a straight line passing through origin.
Conclusion : From the graph between V and I, we conclude that I = V, which is Ohm's law. Hence Ohm's law is verified experimentally. Ohm's law does not hold under all conditions. Ohm's law does not hold for non-ohmic material such as electrotyte.
Posted by Lokeah Kumar 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
o determine focal length of a given concave mirror:
Materials Required
A concave mirror, a measuring scale, a screen a mirror holder and mirror stand.
Procedure
- Select a distant object from the laboratory window (distance should be more than 50 ft).
- Fix the concave mirror on the mirror stand placed on the table, facing the distant object.
- Place the screen in front of the reflecting surface of the mirror. Move the screen back and forth until a clear, sharp image of the distant object is obtained on the screen.
- Measure the distance between the concave mirror and the screen with a metre scale. This distance is the focal length of the given concave mirror. Record the focal length.
- Repeat the above procedure twice and record the readings. Take three readings and calculate the average focal length.
Posted by Tanisha Patel 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Mendeleev's periodic table is an arrangement of the elements that group similar elements together. He left blank spaces for the undiscovered elements (atomic masses, element: 44, scandium; 68, gallium; 72, germanium; & 100, technetium) so that certain elements can be grouped together.
Posted by Uihjku Dtgdrstj 5 years, 1 month ago
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Kumari Shalini 5 years, 1 month ago
Mehak Samra 5 years, 1 month ago
Gaurav Seth 5 years, 1 month ago
Digestion is the process of break down of complex food materials into simpler substances which can be absorbed by blood and transported throughout the body. The digestion process releases energy which is utilized by the cells to carry out various life processes. The digestive tract is a long tube-like structure that starts with the mouth and ends in the large intestine. This tube is known as the alimentary canal
Posted by Neetu Kumari 5 years, 1 month ago
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Ritik Deepak 5 years, 1 month ago
Kumari Shalini 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
The cartilage rings are present in the trachea to prevent it from collapsing. This enables the lumen of the trachea to stay open during breathing.
Encileta Jebakumar 5 years, 1 month ago
Posted by Rudraksh Rai Udaiwal 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
According to lenz’s law, the induced EMF always opposed the cause which is producing it.
If the cause of the induced EMF is a time varying current, then the induced EMF opposes the changes in current and maintaining status quo.
If the cause is growth of current in the loop then, the induced EMF establishes a current in opposite direction opposing the cause. Similarly, if the cause of induced EMF is decay in the current then the induced EMF establishes a current in original current direction, Thus again opposing the growth. Thus, lenz’s law is in accordance with the law of conservation of energy principle.
If lenz’s law is wrong, then the induced EMF support the cause. Then the induced EMF further increases the rate of change of phiB and the induced EMF again supports, if this continues the energy of the circuit goes on which violates the conservation of energy principle.
Posted by Dhrangi Prakash 12 5 years, 1 month ago
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Maahi Chawla 5 years, 1 month ago
Posted by Rani Kumari 5 years, 1 month ago
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Kumari Shalini 5 years, 1 month ago
Posted by Krishnpal Yadav 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
HRD Minister Ramesh Nishank announced a major CBSE syllabus reduction for the new academic year 2020-21 on July 7 which was soon followed by an official notification by CBSE on the same.
Considering the loss of classroom teaching time due to the Covid-19 pandemic and lockdown, CBSE reduced the syllabus of classes 9 to 12 with the help of suggestions from NCERT.
Deleted syllabus of CBSE Class 10 Science
Posted by Raj Wardhan 5 years, 1 month ago
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Posted by Sanket Sundar 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Demerits of Mendeleev Periodic Table
- He was unable to locate hydrogen in the periodic table.
- Increase in atomic mass was not regular while moving from one element to another. Hence, the number of elements yet to be discovered was not predictable.
- Later on, isotopes of elements were found which violated Mendeleev’s periodic law.
Malaika Sharma 5 years, 1 month ago
Posted by Riddhima Joshi 5 years, 1 month ago
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Sruthi Kambar 5 years, 1 month ago
Supriya Mishra 5 years, 1 month ago
Posted by S Viswanath 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Reflection of light is the phenomenon of bouncing back of light in the same medium on striking the surface of any object.
Refraction of light is the phenomenon of change in the path of light in going from one medium to another.
King Adithya H M... 5 years, 1 month ago
Posted by King Adithya H M... 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Posted by King Adithya H M... 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Public facilities are services provided by the government to its citizens. Some of the important public facilities include infrastructure, sanitation, public transport, health care, water, etc. The government's main objective is to provide these public facilities to citizens and businesses to manage social and economic activities more smoothly. Let's look at some of the public facilities in India.
Manshi Kharkwal 5 years, 1 month ago
Posted by Simone Verma 5 years, 1 month ago
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Supriya Mishra 5 years, 1 month ago
Dewang Doye 5 years, 1 month ago
King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Danger signals are red in color because it is scattered the least by air molecules. ... Since the color red has the highest wavelength of all the colors we can see it scattered the least. So, red light is used as a danger signal as it is able to travel the longest distance through the fog, rain, etc.
Posted by Ganesh Deshmukh 5 years, 1 month ago
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Posted by Rubi Kumari 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Following are the precautions while making the image by the help of convex lens:
1) Fix the convex lens vertically in the lens holder.
2) The base of the lens and white screen should be in a line with the measuring scale.
3) Record the position of the lens and screen only when a well-defined sharp image is formed.
4) There should not be an obstacle in the path of the convex lens.
King Adithya H M... 5 years, 1 month ago
Posted by Dhruvi Jain 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Posted by Rubi Kumari 5 years, 1 month ago
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Rubi Kumari 5 years, 1 month ago
Posted by Dhruvi Jain 5 years, 1 month ago
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King Adithya H M... 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Ethanol does not react with dilute sodium hydroxide,
The reason is also correct the ethoxide ion is the stronger base than hydroxide ion.
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King Adithya H M... 5 years, 1 month ago
3Thank You