Biology; Chemistry; Physics: Post your doubts here!

[sourov97]

As the potential difference decreases the current increases right"?? right?
but how will you answer this View attachment 27821s

should the graph not going downwards? like the gradient negative?

Ohms Law:
"the current flowing in a metallic conductor is directly proportional to the potential difference applied across its end, provided that the physical conditions (such as temperature) are constant "...hence V proportional to I .....and V = IR...where R is a constant (resistance of the conductor)

 

[sourov97]

what do you think the answer should be and why View attachment 27820

the image formed by the lens in camera is: i) real ii) inverted iii) diminished
Ans: B

 

[kiara15]

Smallest division of the equipment / value obtained
Worse fit line? I'm sure you meant best fit.

Best fit refers to a line which touches at least two points on the line, and the rest evenly scattered. Say you had 8 plotted 8 points. 3 were on the line. 3 slightly above the line, 2 slightly below or vice versa is acceptable. 4 above 2 below etc are not.

Basically, you see by moving the ruler where the most points fall on the line-to-be and then see how many lie above and below. If out of 8 points 6 lie on the line then go ahead regardless of the other two. If no two points lie neatly/the value difference b/w the other lines is too much then you performed your practical way too inaccurately

thaanks and how to draw worst acceptable line?

 

[kiara15]

Smallest division of the equipment / value obtained
Worse fit line? I'm sure you meant best fit.

Best fit refers to a line which touches at least two points on the line, and the rest evenly scattered. Say you had 8 plotted 8 points. 3 were on the line. 3 slightly above the line, 2 slightly below or vice versa is acceptable. 4 above 2 below etc are not.

Basically, you see by moving the ruler where the most points fall on the line-to-be and then see how many lie above and below. If out of 8 points 6 lie on the line then go ahead regardless of the other two. If no two points lie neatly/the value difference b/w the other lines is too much then you performed your practical way too inaccurately

can u tel me or post picture of how to draw error bars like in quest 2 oct/nov 2009 p52?

 

[AbbbbY]

can u tel me or post picture of how to draw error bars like in quest 2 oct/nov 2009 p52?

Is this A Level or O Leve?

 

[sourov97]

the ans should be A or B...but how can the rays pass the lens without being refracted!??
which year??

rays passing through the optical center passes without bending.

 

[Salman Rahman]

rays passing through the optical center passes without bending.

ohh!..sorry!...i missed it .

 

[Zuhsid]

So now.... the answer to the phy MCQ as to what happens to the voltmeter and ammeter readings if the filament in lamp 1 broke..... is that..... Ammeter reading decreases and voltmeter reading increases.... those of you who did it wrong...... Join the club!!

 

[Kamihus]

So now.... the answer to the phy MCQ as to what happens to the voltmeter and ammeter readings if the filament in lamp 1 broke..... is that..... Ammeter reading decreases and voltmeter reading increases.... those of you who did it wrong...... Join the club!!

is there anyone like who did the opposite?

 

[Zuhsid]

is there anyone like who did the opposite?

I did.... u did it ryt?

 

[Zuhsid]

Yup i did it but probably its wrong

As in u did what i said in the first post?

 

[Kamihus]

As in u did what i said in the first post?

i did current increase and voltage decrease

 

[Zuhsid]

i did current increase and voltage decrease

Literally everyone did that!!

 

[Snowysangel]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Biology (5090)/5090_s12_qp_12.pdf could someone explain questions 26 and 40 to me?

 

[Kamihus]

Literally everyone did that!!

everyone i asked did the other one

 

[Snowysangel]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Biology (5090)/5090_s12_qp_12.pdf could someone explain questions 26 and 40 to me?

how on earth are we even supposed to know the answer to q26?

 

[Kamihus]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Biology (5090)/5090_s12_qp_12.pdf could someone explain questions 26 and 40 to me?

26)Decomposition of the oil will be fastest when microorganisms are stimulated by aerobic conditions or raising the temperature. Wave action will result in smaller oil drops with more surface area.
40)There are two distinct groups of offspring, such as in the cross of a heterozygous tall strain of pea with a homozygous short one. The groups are separated by 21cm. Within each group there is continuous variation.

 

[Snowysangel]

26)Decomposition of the oil will be fastest when microorganisms are stimulated by aerobic conditions or raising the temperature. Wave action will result in smaller oil drops with more surface area.
40)There are two distinct groups of offspring, such as in the cross of a heterozygous tall strain of pea with a homozygous short one. The groups are separated by 21cm. Within each group there is continuous variation.

but wont hot water denature the enzymes in the microbes? i still dont get q40. what two distinct groups of offsprings? how do a heterozygous and a homozygous recessive produce two clearcut offsprings? their ratio will be 1:1 so theyre either tall or short...is that it?

 

[KWIKIW]

How to do those heart graphs and also which muscles contract when a bolus of food is passing during peristalsis?

 

[Snowysangel]

How to do those heart graphs and also which muscles contract when a bolus of food is passing during peristalsis?

the longitudinal muscles contract in the region where the bolus is, and in the part of the gut right before the bolus, the circular muscles contract and the longitudinal relax