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[A] : Every biological system resists a ...

[A] : Every biological system resists a change and wants to remain in a state of equilibrium .
[R] : Climax communities of an ecosystem are produced after several changes it has gone through succession .

A

If both A and R are true and R is the correct explanation of A

B

If both A and R are true but R is not the correct explanation of A

C

If A is true and R is false

D

If both A and R are false

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Figure shows a wire ab of length L and resistance R which can slide on a smooth pair of rails. I_(g) is current generator which supplies a constant current i in the circuit. If the wire ab slide at a speed v towards right, find the potential difference below a and b (b) The current generator I_(g) show in the figure sends a constant current i through the circiut. The wire ab has a length L and mass m and can slide on the smooth horizontal rails connect to I_(g) . The entire system lies in a vertical magnetic field B . Find the velocity of the wire as a function of time. (c) The system containing the rails and the wire of the previous part is kept vertically in a uniform horizontal magnetic field B that is perpendicular to the plane of the rails (figure). If is found that the wire stays in equilibrium. If th ewire ab is replaced by another wire of double its mass, how long will lit take in falling through a distance equal to its length? The current generator I_(g) shown in figure sends a constant current i through the circuit. The wire cd is fixed and wire ab is made to slide on the smooth, thick rails with a constant velocity v toward right. Each of these wires has resistance r . Find the current through the wire cd .

A metaillic circular loop of radius r is placed in unfirom magnetic field B acting perpendicular to the plane of the loop . A naughty boy pulls dimetrically oppsite corner so that after sometime, the loop changes into an ellipse of major and minor radius a and b . It total resistance of loop is R and it remains constant during the puilling . Find average change flowing through loop during pulling .

A ball is projected on a very long floor. There may be two conditions (i) floor is smooth & (ii) the collision is elastic If both the considered then the path of ball is as follows. Now if collision is inelastic and surface is rough then the path is as follows. Successive range is decreasing . Roughness of surface decreases the horizontal component of ball during collision and inelastic nature of collision decreases the vertical component of velocity of ball. In first case both components remain unchanged in magnitude and in second case both the components of the velocity will change. Let us consider a third case here surface is rough but the collision of ball with floor is elastic. A ball is projected withe speed u at an angle 30^(@) with horizontal and it is known that after collision with the floor its speed becomes (u)/(sqrt(3)) . Then answer the following questions. If the ball after first collision with the floor has rebounded vertically then the speed of the ball just after the collision with the floor would have been :

Read the following statements and state how many of them are true ? (P) primary succession , is a very slow process taking thousands of years for the climax to be reached . (Q) All succession whether taking place in water or land proceeds ti a similar climax community, the mesic. (R) As succession proceeds, the number and types of animals and decomposers also change. (S) Saprophytes are not given any place in the ecological pyramids as they play no role in the ecosystem.

TRUEMAN BIOLOGY-Ecology -ASSERTION AND REASON
  1. [A] : The community that ends in a succession is known as climax commu...

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  2. [A] : A biotic community exhibits adaptive radiation . [R] : The org...

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  3. [A] : Every biological system resists a change and wants to remain in ...

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  4. [A] : Allopatric species are geographically isolated whereas sympatric...

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  5. [A] : Natural populations are capable of an enormous and rapid increas...

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  6. [A] : In mutualism both the individuals are benefitted . [R] : Both ...

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  7. [A] : Stenothermal species can tolerate narrow range of temperatures ....

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  8. [A] Eurythermic plants can withstand wide range of temperature . [R...

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  9. [A] : Light is the energy which is stored as chemical energy in the fo...

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  10. [A] : Flora and Fauna of different parts of the world do not show unif...

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  11. [A] : A species is an interbreeding population which is reproductively...

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  12. [A] : Mimicry is a device adopted to protect the organism from its ene...

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  13. [A] : Biological magnification is concentration of substances instead ...

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  14. [A] : The rate of energy storage at consumer levels are referred to as...

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  15. [A] : Primary productivity is shown by green plants only . [R] : Pri...

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  16. [A] : Energy pyramid is sloping . [R] : The energy of one trophic le...

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  17. [A] : The biotic community and the non living enviroment of an ara fun...

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  18. [A] :Green plants ara secondary consumers [R]: Microconsumers break...

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  19. [A] : A food chain is a group of organism in which there is a transfer...

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  20. [A] : Food chains are not paths of energy flow throgh and ecosysterm. ...

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