Population structure
Population refers to the individuals living or inhabiting in the same area at the same time.Its dynamics depends upon age,density,dispersion,size & speciation. Factors of population: 1.Natality:no. of individuals added through birth. 2.Mortality:no. of individuals removed through death. Population density:no. of individuals in a population per unit habit area.It depends on structure ,age & mating. A speciation in a population dynamics involves generation or formation of new species through evolution that may occur in a particular geographical area. Types of speciation: 1.Sympatric:When new & existing species live in same geographical area at same time period. 2.Allopatric:When different species live in diiferent geographical ares but at same period of time. 3.Parapatric:Addition of new species to a new geographical area which may lead to positive & negative interactions between population groups which may lead to deletion of a few selected species. Population dispersion can be in the form of cluster,clump,uniform or random. Fluctuation in a population may occur due to environmental changes. Population studies are represented as demographs,Its a graphical way of representing population statics,they are usually related to a no. of 1000 or more.They can be in the form of stable,expanding or declining structure. Population growth depends on biotic & abiotic factors,they are charachterised as both generalised & logical.In generalised form there are four phases such the lag phase which is the early growth phase,log phase which is the exponential phase,stationary or stable phase & declining or death phase.In logical form,it is assumed that more no. of population are found in that particular period of time. Survivalship curve refers to an organisms adapatation & its ability to reproduce naturally under a given duration of time which later on represented in the form of a graph. Factors influencing population growth are natural calamities,birth & death rate,increased predation,competetion for food & other resources & disease.
Rajnandini Saha
Magnetic effects of current
The rate of flow of charge is called current.It is always directed from +ve to -ve terminal of the circuit.It is a scalar quantity as it doesn't obey the law of vector addition.Its S.I unit is Ampere. Ohm's law:The potential difference across the two ends of the resisitor is directly proportional to current flowing through it provided the temparature remains same. V=IR The opposition to the flow of current is called resistance .It depends upon length,cross-sectional area ,temparature & the nature of the material.Its S.I unit is ohm. R=pL/A where,p is the resistivity of the material. Biot-Savart law The magnitude of a magnetic field at any point due to a current carrying conductor depends upon the current flowing through it,the length element,sin of angle between the position vector and current & inversely proportional to the square of distance of the point from the conductor. ~applications~ 1.Magnetic field due to a straight current carrying conductor. 2.Magnetic field at the centre of the current carrying coil. 3.Magnetic field at the axis of the current carrying coil. Lorentz force When a charge particle moves in a region having both electric & magnetic field then it will experience force by both electric & magnetic field.The vector sum of these two field together is called lorentz force. Cyclotron It is a device which is used to accelerate charge particles in successive steps under the influence of both electric & magnetic field.It consists of two DeesThe electric field helps in accerlation of the particles & the magnetic field helps in circulation of those charged particles in the two semicircular hollow dees separated by a small distance which is set by an alternate source.The whole setup is placed perpendicularly between two pole pieces of magnet.It is only applicable for charged particles because of the relativistic increase in the mass of the charged particles which makes it less energetic.
Electromagnetic Induction
The no. of magnetic field lines passing perpendicularly to a surface is called as magnetic flux.Its S.I unit is Tesla m2 Faraday's experiment He maintained arelative motion between a magnet & a closed coil containing a galvanometer.He found that whenever the northpole of a magnet was moving away or toward the coil the galvanometer showed deflection.This shows that due to the presence of magnet some field lines are connected to the coil,whenever the position of the coil changes the magnetic field lines linked with the coil also changes. For this,an emf is induced in the coil which lasts as long as the change in magnetic flux continues.This is called electromagnetic induction. Lenzs law An emf is produced in the coil such that it opposes the cause which produces it. Whenever the northpole of the magnet was moved towards the coil an induced current is generated in an anticlockwise manner & if the northpole of the magnet is moved away from the coil,the induced current is generated in the clockwise manner. Motional emf The developement of emf in a conductor or a coil when it is moved in a fixed magnetic field. Self-induction Whenever there's a change in emf in a conductor or a coil due to change in its own current is called self-induction Mutual-induction Whenever there's a change in the secondary coil due to the change in current in the primary coil is called mutual induction.
Overcoming Challenges
Everything we are currently experiencing in our lives comes about in order to assist us in evolving to a higher level of consciousness.Even what we now perceive as bad,sad,negative or upsetting is here to assist us in seeing life in a more peaceful,forgiving and loving way.Each one of us is shaped into a distinctive cut of stone,giving way to different grades of clarity and colour,making us rare,valuable,and uniquely our own.Personal challenges encourage us to grow as an individual and make better choices for a brighter future. In life,we came across many challenges let it be your worries,fears,the day-to-day obstacles,reality of financial aid,relationship issues or impulsiveness.If we are born in this world then we need to face these obstacles to lead in life.In our lifetime we experience tough and difficult challenges.Bad things do happen,but how to respond them defines the character and quality of both,the person and life.A person can choose to sit in perpetual sadness,immobilized by the gravity of loss,or can choose to rise from the pain and treasure ,the most precious gift one can receive. Sometimes these challenges become unbearable,especially when the odds are against you.However,going against all odds is something everyone is capable of doing,and to overcome these challenges everyone needs to have a “never quit” attitude in life.If we develop it,we’ll overcome quite a bit. Nobody is perfect but they are surely near to perfection,you may encounter many defeats,but you must not be defeated for sure.In fact,it may be necessary to encounter the defeats,so you can know who you are,what you can rise from,how you can still come out of it.Many people all around the world face challenges and obstacles in their daily life and we all are victims of these challenges. As one of the most notable and accomplished football coaches in history,Vince Lombardireally knows what it means to overcome challenges.He’s one of the most successful coaches in the history of American football as head of coach of the Green Bay Packersfrom 1959-1967 and the Washington Redskins in 1969. If you have a positive attitude and constantly strive to give your best effort,eventually you will overcome your immediate problems and find you are ready for greater challenges.Challenges are what make life interesting and overcoming them is what makes life meaningful.
Resist And Reignite
There’s always a reason behind everything we get in our life.You can’t make everyone happy.If it is your goal ,you are bound to lose yourself.People face circumstances in every walk of life but also enjoy the blissful outcomes.You & your soul be tired of managing everyday’s routine but have you ever thought of making life simple again?You went through several hard situations but that doesn’t mean you’ll pretend to be happy when you are not.At some point of time,you must have thought of an aspect of your life is “wrong” ,stop labeling anything or anyone as right or wrong.It’s not possible to go for the right thing always, you repeat negative patterns to seek what life is teaching you,then embrace a positive change.Making mistakes is in human nature,learn from them,laugh about them and move along.You can be the most positive and enthusiastic person.Think big thoughts but relish in small pleasures.Treat everyone you meet like you want to be treated.Trust that what you want will flow if you create good feelings each day and allow divine order. Happiness is not the treasure to be found but can be built within ourselves.The only way to be happy is to make others happy.Surround yourself with people who fill your gaps.You’re rigidly attached to your opinions instead open yourself to others,as you upgrade your mind ,you upgrade your life.Always strive for excellence not perfection.Being perfect is unrealistic.Don’t expect life to be fair.Live your life as an exclamation.You look for barriers to your progress.Instead anticipate miracles will happen and be ready for the universe to surprise you! Compliment yourself even in small improvements that’s how you’ll get to know where you stand and how better you can be.Always keep your promises.Rekindle old friendships and connect to the people as much as you can because material possessions won’t make you better or happier. Explore new ideas and opportunities often and set your priorities.You’ll die and you have no idea when,grasp every moment.Live on auto-pilot mode…whatever happens…happens.So,let it be.Practise acceptance and be curious about how life is guiding you.Be a better version of yourself.Your achievements and success won’t matter as much as your precious memories on your deathbed.It’s just the little things in life which must be cherished forever.