Biology; Chemistry; Physics: Post your doubts here!

[***amd***]

In this part they're asking about the 'observable differences' that you have mentioned in the previous part. So you gotta link your answer to that. I guess. Not sure.

but "more air spaces" is also one of those 'observable differences'

 

[exploded diper]

View attachment 40614

u do know tht ur crosses r too big.....it says they should be half the size of a small square.......

 

[Awesome12]

u do know tht ur crosses r too big.....it says they should be half the size of a small square.......

I did that deliberately. When i took the pic, the crosses were very vague, and to make them more clear as to where the line passes, I darkened ad made them bigger

 

[Awesome12]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Biology (5090)/5090_s12_ms_62.pdf
Q1 (c) (ii)
why cant we give reference to "more transpiration in in leaves in light because of more air spaces to cop with the more heat of sun" here?

The last part is wrong. Air spaces just don't cope with the heat of the Sun. Infact, if you wrote more air spaces allow more water to move out of the leaf, or more CO2 allowed, thus more photosynthesis and more water is produced, then your answer would be correct.
In Bio, you have to be as specific as you can

 

[Awesome12]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Biology (5090)/5090_w07_qp_1.pdf
Question 6 ? Why cant the answer be b? As CO2 is entering into the test tube b, which is acidic in nature so the ph would fall below 7, no?
Question 13? I dont get this AT ALL! :'(
Question 28? The sun being the ultimate source of energy would provide energy to both the consumer and the producer. Why can't the answer be as as every living organism takes energy from sun independently, apart from the energy flowing from the producer to the consumer.

6) CO2 is being released in the first test tube due to respiration. CO2 is acidic, and it lowers pH, thus it can't be 7

13) The 4 valves of the heart are not all closed simultaneously, except for a very short period of time. Thus it is B

28) Do we take energy from the Sun?

 

[Mahnoorfatima]

have u seen any human ever making food by using suns energy directly....

6) CO2 is being released in the first test tube due to respiration. CO2 is acidic, and it lowers pH, thus it can't be 7

13) The 4 valves of the heart are not all closed simultaneously, except for a very short period of time. Thus it is B

28) Do we take energy from the Sun?

Don't we get energy from the sun? I read it somewhere that the "Ultimate source of energy for all the living organisms including us is the sun" Wow tthats what our bio teacher said.

 

[Awesome12]

Don't we get energy from the sun? I read it somewhere that the "Ultimate source of energy for all the living organisms including us is the sun" Wow tthats what our bio teacher said.

It means that plants actually use energy from the Sun, and then when we feed on producers and consumers, we obtain this CONVERTED Energy

 

[Mahnoorfatima]

It means that plants actually use energy from the Sun, and then when we feed on producers and consumers, we obtain this CONVERTED Energy

Oh lol right.

 

[funky brat]

Don't we get energy from the sun? I read it somewhere that the "Ultimate source of energy for all the living organisms including us is the sun" Wow tthats what our bio teacher said.

We ain't solar panels.
I mean how can you take the sun's energy directly? It has to flow through the producers. Humans are hetertotroph, they don't make their food themselves, plants are autotrophs.

 

[Mahnoorfatima]

We ain't solar panels.
I mean how can you take the sun's energy directly? It has to flow through the producers. Humans are hetertotroph, they don't make their food themselves, plants are autotrophs.

Alright! I got it btw. Thanks anyway.

 

[funky brat]

Which application may use the part of the electromagnetic spectrum called microwaves?
A cooking vegetables (this is the correct answer)
B detecting small cracks in metals
C gaining a sun-tan
D lighting a fluorescent tube

can anyone explain me
funky brat

Actually there are some frequencies that food absorbs well and microwave has the right frequency. This principle is used to make microwave ovens. Apart from even other options are incorrect. Ultraviolet rays give you sun tan. Even in option D, ultraviolet rays are important. For detecting cracks, waves with high frequency will be suitable so the answer is A.
Sorry for the late reply.

 

[funky brat]

what is the use of millibar ?

That's not in our syllabus, I guess.

 

[funky brat]

what is the correct voltage against current graph.....and current against voltage....for ohmic conductors.....................

Voltage against current is straight line passing through origin.

 

[exploded diper]

Don't we get energy from the sun? I read it somewhere that the "Ultimate source of energy for all the living organisms including us is the sun" Wow tthats what our bio teacher said.

thts becuz we eat producer which get their energy from it.....its the ultimate energy not in the direct form....

 

[exploded diper]

Voltage against current is straight line passing through origin.

u mean voltage as y axis right?

 

[funky brat]

Yeah

 

[exploded diper]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w12_qp_41.pdf
what is th answer to a 1

 

[funky brat]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w12_qp_41.pdf
what is th answer to a 1

When it is released after pulling, it will be in it's original position. That is the one shown in 1.1a

 

[exploded diper]

When it is released after pulling, it will be in it's original position. That is the one shown in 1.1a

thx...

 

[***amd***]

The last part is wrong. Air spaces just don't cope with the heat of the Sun. Infact, if you wrote more air spaces allow more water to move out of the leaf, or more CO2 allowed, thus more photosynthesis and more water is produced, then your answer would be correct.
In Bio, you have to be as specific as you can

but more air spaces means more transpiration, no?