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Ask QuestionPosted by Murtuza Kɦan 5 years, 4 months ago
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Satyam Lodhi Rajput 5 years, 4 months ago
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Satyam Lodhi Rajput 5 years, 4 months ago
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
The emission of free electrons from a metal surface when the light is shone on it, it is called the photoemission or the photoelectric effect. This effect led to the conclusion that light is made up of packets or quantum of energy. Now the question was whether the light quantum theory was indicative of the particle nature of light. Einstein already associated the light quantum with momentum. This strongly supported the particle nature of light and these particles were named photons. Thus, the wave-particle duality of light came into the picture.
Photoelectric Emission
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Meghna Thapar 5 years, 2 months ago
In optics, the corpuscular theory of light, arguably set forward by Descartes in 1637, states that light is made up of small discrete particles called "corpuscles" which travel in a straight line with a finite velocity and possess impetus. This was based on an alternate description of atomism of the time period. The model of light and the particle model of light, which together describe the wave-particle duality in which light is understood to possess both wave and particle functions. The wave theory and the particle theory of light were long considered to be at odds with one another.
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
Huygens’ wave theory of light: In 1678, Dutch physicist Christian Huygens proposed a theory to explain the wave nature of light. This theory is called Huygens’ wave theory of light. According to wave theory of light, a source of light sends out disturbance in all directions. When these waves carrying energy reach the eye, they excite the optic nerves and the sensation of vision is produced. Main postulates of Huygens’ wave theory:
i. Light energy from a source is propagated in the form of waves: The particles of the medium vibrate about their mean positions in the form of simple harmonic motion. Thus, the particles transfer energy from one particle to its neighbouring particle and reach the observer.
ii. In homogeneous isotropic medium, the velocity of wave remains constant: Speed of the wave is not affected because density and temperature of isotropic medium are same throughout.
iii. Different colours of light waves are due to different wavelengths of light waves: Each wave has its own wavelength. As the wavelength changes, its colour and frequency also changes. This is indicated by change in the colour.
iv. The material medium is necessary for the propagation of wave: Periodic disturbance is created in the medium at one place which is propagated from that place to another place. The medium only carries disturbance and hand it over to the next particle. To explain the propagation of light waves through vacuum, Huygens suggested the existence of a hypothetical medium called ‘luminiferous ether’.
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Navnidhi Gandhi 5 years, 4 months ago
Yogita Ingle 5 years, 4 months ago
Sodium and Potassium are the two metals which can be cut with a knife.
Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Posted by Satyam Lodhi Rajput 5 years, 4 months ago
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Geeta Jadav 5 years, 4 months ago
Posted by Nitin Joshi 5 years, 4 months ago
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Meghna Thapar 5 years, 1 month ago
A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. There are many examples of forces in our everyday lives: weight force (i.e. the weight of something) the force of a bat on the ball. the force of the hair brush on hair when it is being brushed. A force is a push or pull acting upon an object as a result of its interaction with another object. ... Previously in this lesson, a variety of force types were placed into two broad category headings on the basis of whether the force resulted from the contact or non-contact of the two interacting objects.
Posted by Rishi Kishore 5 years, 4 months ago
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Aaman Khan 5 years, 4 months ago
Gaurav Seth 5 years, 4 months ago
Ohm’s Law
George Simon ohm(in 1826)studied relationship between I and V across the ends of conductor.
Ohm’s Law states that electric current flowing in a conductor is directly proportional to potential difference across the ends of the conductor,provided temperature and other physical conditions remains constant.
V=IR
R=Resistance of conductor
Resistance of a conductor is the property of conductor to oppose the flow of charge through it.
R = V/I
Unit of resistance is ohm
1 ohm = 1 Volt / 1 Ampere
Resistance of a conductor is said to be 1 ohm if a potential difference of 1 volts across the ends of conductor makes a current of 1 ampere to flow through it.
Slope = I / V
Slope of graph V and I=Resistance of a conductor
V=IR
I= V/R
If R is halved then I is doubled.
If R is doubled then I is halved.
Posted by Rishi Kishore 5 years, 4 months ago
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Gaurav Seth 5 years, 4 months ago
Electric potential at a point in an Electric field (for instance, let's take it as uniform) is the amount of work done in moving a unit positive charge from infinity to that point against electric forces. (attraction or repulsion)
whereas Electric potential difference between two points in an Electric field is defined as the amount of work done in moving unit positive charge from one point to another point against the electric force.
In other words, Potential difference is simply the difference of scalar potentials between two points or anything you consider...
Now let's take an example.
Say, you're placing a charge (+q) at the point O. Also, There are two points A & B in the electric field E(It acts outward since the line charge is positive). Now, you want to move a charge (say +q) from B to A. Then, you've to do some work against the force of repulsion. This work done is the potential difference between two points or Voltage (i.e.) WB?A=dV which further equals ?E.dx. Electric field is simply the force experienced by unit positive charge.
If you bring the same charge from ? instead of B, it's electric potential. Using the above figure & integrating for total work done (with limits ? to some scalar distance r), one could derive Electric potential at a point. It's given by V=q4??r. But, you could ask, "Why this work is not stored as some potential energy?"
Yes, It is. But, Potential energy requires the magnitude of another charge also... If r is the distance of separation of two charges, P.E. is given by Ep=qQ4??r. In other words, Ep=VQ
Posted by Rishi Kishore 5 years, 4 months ago
- 1 answers
Gaurav Seth 5 years, 4 months ago
1. Regeneration means the regrowth of a damaged or missing organ part from the remaining tissue. As adults, humans can regenerate some organs, such as the liver. If part of the liver is lost by disease or injury, the liver grows back to its original size, though not its original shape.
2. Budding is a type of asexual reproduction in which there is a continuous regeneration of cells at one specific site on the body of an organism. A bud grows as an outgrowth on that site.
3.
- The cutting, layering and grafting are all the methods of vegetative propagation.
- The vegetative propagation is the process through which the progeny plants develop from the parent plant.
- The cutting process involves the cutting of the stem part of the plant and grown in the soil, the stem develops roots and leaves and new plants are grown through this way.
- The layering process occurs when from the same parent stem many branches develop each stem develop a root system and live as an individual plant.
- The grafting is the process through which a stem is cut and tied over other plant stem this way the quality of both plants will retain in a single plant.
Tissue culture is a technique of developing an organ or tissue in a laboratory using fragments of tissues and organs, on a nutrient media for proper development.
Posted by Shivangi Dixit 5 years, 4 months ago
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Posted by Priyanka Kumari 5 years, 4 months ago
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Rishi Kishore 5 years, 4 months ago
Posted by Jaat Shab 5 years, 4 months ago
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Tanishq Mangla 5 years, 4 months ago
Posted by Harshit Yadav 5 years, 4 months ago
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Gaurav Seth 5 years, 4 months ago
The reaction between calcium oxide (CaO) and water (H2O) to form calcium hydroxide Ca(OH)2 is an exothermic combination reaction.
This is because: Calcium oxide reacts with water to form slaked lime Ca(OH)2 which means the oxides of calcium combine with molecules of free molecules of O- and H+
This reaction generates a lot of heat accompanied with hissing sound and thus is stated to be exothermic.
Posted by Nisha???????? Bharti 5 years, 4 months ago
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Posted by Kalu Bhosale 5 years, 4 months ago
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Learner Kumar 5 years, 4 months ago
Rashmi Sinha 5 years, 4 months ago
Posted by Disha Agarwal 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
A process where a DNA molecule produces two similar copies of itself in a reproducing cell is called DNA copying.
Its importance are:
- It makes the transmission of characters from parents to the next generation possible.
- It causes variation in the population.
Apurv Rai 5 years, 4 months ago
Posted by Disha Agarwal 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
A process where a DNA molecule produces two similar copies of itself in a reproducing cell is called DNA copying.
Its importance are:
- It makes the transmission of characters from parents to the next generation possible.
- It causes variation in the population.
Posted by Arghyadeep Laskar 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
Rhizopus is the species of a fungus. They reproduce asexually by the formation of the spores. The body of the fungus is composed of the hyphae which develop the sporangium. The sporangium is a swollen structure at the tip of the filaments bearing the spores. The spores are tough and resistant structures which are dispersed by the breaking of the sporangium. When the conditions are favourable, then these spores germinate and develop to form new fungal filaments.
Posted by Anupama ?? 5 years, 4 months ago
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Chahat Modi 5 years, 4 months ago
Posted by Vanshika Verma 5 years, 4 months ago
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Anupama ?? 5 years, 4 months ago
Posted by Mega K 5 years, 4 months ago
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Posted by Geeta Jadav 5 years, 4 months ago
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Geeta Jadav 5 years, 4 months ago
Geeta Jadav 5 years, 4 months ago
Yogita Ingle 5 years, 4 months ago
Given 7×11×13+13 =13×(7×11+1)=3×78
This number is multiple of two integers.Hence it has more than two factors.Hence it is a composite number.
similarly in
7×6×5×4×3 ×2×1+5
=5(7×6×4×3 ×2×1+1)=5×1009
This number is multiple of two integers. Hence it has more than two factors. Hence it is a composite number.
Posted by Luke Lukas 5 years, 4 months ago
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Geeta Jadav 5 years, 4 months ago
Yogita Ingle 5 years, 4 months ago
Thermometer is a device which is used to measure temperature. Thermometer is made of a long narrow glass tube; with a bulb at one end. The narrow tube appears as a continuous silver line; because it is filled with mercury. Mercury is a metal which is in liquid state at room temperature and it readily expands or contracts at the slightest change in temperature. Hence, mercury is used in thermometer.
Posted by Tejasvini S 5 years, 4 months ago
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Gaurav Seth 5 years, 4 months ago
Oxygen molecule splits into atomic oxygen (O) at higher levels of an atmosphere because of higher energy of UV radiations.
So, O2⟶O+O
O2+O⟶O3 (Ozone)
Damage to the ozone layer is a cause of concern to us as it forms a layer in the atmosphere which protects us from the harmful UV radiation.
Damage to ozone layer can cause penetration of UV rays in the earth surface which damages human organs, plants, etc.
Posted by Ishan Chahaliya 5 years, 4 months ago
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Anupama ?? 5 years, 4 months ago
Yogita Ingle 5 years, 4 months ago
White blood cells (Leucocytes)
Leucocytes are the colourless blood cells. They are colourless because it is devoid of haemoglobin. They are further classified as granulocytes and agranulocytes. WBCs mainly contribute to immunity and defence mechanism
Posted by Âyush Kumar 5 years, 4 months ago
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Yogita Ingle 5 years, 4 months ago
In its uncultivated form, <i>Brassica oleracea</i> is known as wild cabbage. The family includes cabbage, kale, collards, cauliflower, broccoli, kohlrabi, and brussels sprouts, each variety is chosen for certain traits like flower buds, large leaves, and edible stems. Artificial selection is a process in which humans consciously select for or against particular features in organisms. Artificial selection has enabled the cultivation of new crops with desirable traits from one single common ancestor. Furthermore, once a plant with the combination of alleles for a desired phenotype is produced, it can be propagated asexually by taking cuttings, grafting and encouraging runners or through layering. By artificial selection, man has produced many crop plants like broccoli, cabbage, cauliflower, kohlrabi etc. from a common wild cabbage species by selective breeding and artificial selection.
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Yogita Ingle 5 years, 4 months ago
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