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Biology; Chemistry; Physics: Post your doubts here!

Ishrar Afrida

Ishrar Afrida

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Hskk said:
Yes. Cu ions form a ppt in excess of sodium hydroxide and dissolve in excess aq. ammonia, since they're replacing sodium hydroxide with ammonia, the ppt will dissolve to give a deep blue solution.
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Now I'm confused. :/
 
usama321

usama321

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Amnaa said:
can any one please guide me in extension topic of physics.. i mostly attempt wrong choice in paper1.. :(
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Mostly in paper one, the question is about the limit of proportionality of a spring. According to Hooke's law, force = k* extension, where k is constant, so that with an increase in force, the extension of the spring should be the same. E-g lets say we add a weight of 2N to a spring, and its length increases by 2cm. Now for the next 2 N, the length should again increase only by 2cm. That is we have a constant increase.

But the limit of proportionality is when the spring stops obeying hooke's law, and its extensions starts increasing non uniformly, like 4 cm for the same 2N weight. When this happens, the spring is permanently deformed, and the total weight at which this happened is the limit of proportionality of the spring.
 
A

Amen

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4 part a. in root xylem is always star shaped whereas in stem it is always present towards the inner side dat is towards the pith


4 part c. take two plants of same specie,size,age and mass.cut one plant from its while placed in water to present air entering the plant, place both plants in the solutions of same concentration for a few hours .keep all other conditions such as light,temperature constant.then by measuring the drop in the level of solution u can determine easily which plant takes up water more quickly.for greater accuracy repeat the experiment a few times.

HOPE THIS HELPS:)
 
Princess Raven

Princess Raven

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Amen said:
4 part a. in root xylem is always star shaped whereas in stem it is always present towards the inner side dat is towards the pith


4 part c. take two plants of same specie,size,age and mass.cut one plant from its while placed in water to present air entering the plant, place both plants in the solutions of same concentration for a few hours .keep all other conditions such as light,temperature constant.then by measuring the drop in the level of solution u can determine easily which plant takes up water more quickly.for greater accuracy repeat the experiment a few times.

HOPE THIS HELPS:)
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thanks just one q y do we have to cut the plant as u mentioned?
 
chocolate_girl

chocolate_girl

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Can someone tell me the mechanism of curling of stem in bio chap osmosis. I dont understand it at all that y it curls and when it curls inward and outwards like in different concentrations. Please help :)
 
chocolate_girl

chocolate_girl

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Also another problem is in the topic surface area to volume ratio in cells. This thing doesnt get into my head so someone please precisely explain the topic to me :)
 
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