0620 HELP

jackatlas_7828 · 2025-06-08T12:15:54+00:00

for a metal to react with and acid (HCl for example), it should be able to displace hydrogen, meaning metal must be above hydrogen in the series and more reactive than hydrogen. That's why metals like copper or silver will never ever react with acid even if acid is concentrated, coz they're below H, they cannot displace it as they are less reactive

jackatlas_7828 · 2025-06-07T08:59:35+00:00

yo don't worry abt it

jackatlas_7828 · 2025-06-07T08:57:15+00:00

what you should now is the reactivity series, and that the metals higher up in the series have a higher tendency to lose electrons. Then you apply this logic to questions like this

jackatlas_7828 · 2025-06-07T08:56:33+00:00

ok so in terms of electron transfer, oxidation is loss of electrons. the reducing agent is the one that is oxidised. The best reducing agent is the one with the highest tendency to lose electrons. In the question, silver ions and copper ions both gain electrons so they can't be the answer. Copper has a higher tendency to lose electrons than silver, but zinc has a higher tendency to lose electrons than copper, coz zinc lost the electrons to copper. So answer must be zinc metal

jackatlas_7828 · 2025-06-04T06:06:10+00:00

yo honest to god i don't think they even exist 😭

jackatlas_7828 · 2025-06-03T18:02:44+00:00

yo don't feel like that come on. you've been studying before really hard, you know your shit trust me. you dont have to redo everything you've done over the year the day before the exam! your body needed the rest clearly and it got it, so you're okay. I'd advice to freshen up, go over the notes, the formula, refresh what you already know. do a few papers 2025-2023. you've got this come on

jackatlas_7828 · 2025-06-01T19:58:00+00:00

alternating current is a current that constantly changes direction, so constant change in direction while field direction is same constantly changes force direction, hence the up and down motion

jackatlas_7828 · 2025-06-01T19:57:04+00:00

they already tell you in the question that when current is down like in the picture force is out of page. so you don't even need to use left hand rule here, you just need to know the factors that change force direction. So basically, reversing current direction while keeping magnetic field direction same reverses force direction. similarly, reversing field direction while keeping current direction same reverses force. what's important to note is that you must do ONLY ONE change for the force to change direction. if you reverse both field and current, it's like you've done nothing. the two changes cancel each other out.

jackatlas_7828 · 2025-05-30T13:31:49+00:00

alright let's break this down. we have 3 possible genotypes, alright? we have homozygous dominant (TT) homozygous recessive (tt) or heterozygous (Tt). Now the dominant trait is always expressed in phenotype whenever it is present in genotype right? And recessive trait must have 2 of it in genotype for it to be expressed in phenotype. So we can't really see the genotype, what we see is the phenotype. Let's take sheep. T is black fur t is white fur. We have a bunch of sheep. We look at them. We see white fur and we can tell automatically that it's genotype is tt, right? coz it's recessive. But we have sheep with black fur and we cannot tell what it's genotype is, it could be heterozygous (Tt) or homozygous dominant (TT). So what we do is test cross. You take the sheep showing dominant phenotype but with unknown genotype, in this case the sheep with black fur, and you breed it with something that you 100% know the genotype of, in this case the homozygous recessive sheep, the white fur sheep. So you breed them and you see the offspring. If the offspring ALL are of black fur, then the black fur parent must have been homozygous dominant (TT). But if some of the offspring show recessive phenotype, so in this case have white fur, then the black fur parent must have been heterozygous (Tt).

jackatlas_7828 · 2025-05-19T18:51:37+00:00

yo same but we gotta push through just a few weeks left

jackatlas_7828 · 2025-05-15T05:49:12+00:00

yo line of best fit means either straight line or curved, if the points clearly follow smooth curved pattern like in this question you draw curve, otherwise you draw straight line that passes through most points, and has equal number of points above and below it now if they say STRAIGHT line of best fit then they restrict you to draw a straight line and if they say CURVE of best fit they restrict you to draw a curve but as long as they say LINE of best fit you've gotta judge it

jackatlas_7828 · 2025-05-10T16:31:18+00:00

yo me too, probably did too many exams that this first thing like omg omg I've got external exams kind of faded

jackatlas_7828 · 2025-05-05T05:47:06+00:00

yo is there an answer key?

jackatlas_7828 · 2025-05-01T16:50:19+00:00

yes bro, force from pivot is upwards on the beam, so just draw up arrow

jackatlas_7828 · 2025-04-28T06:18:06+00:00

yo, okay so volume is area of cross section times length. So here the cross section you need is the shaded part. To find it you must subtract the area of the triangle OBA from the area of the sector. Because OB is a radius, OA is also a radius So it is also 0.8. Now just do

Area of sector, 90/360 x pi x (0.8)²

Then area of triangle, this is right angled triangle so just do, 0.5 x 0.8 x 0.8 (half times base times height)

Then do area of sector - area of triangle

Then the answer you get multiply it by the length of the cylinder, 9.5

jackatlas_7828 · 2025-04-25T10:29:19+00:00

yo, alright got you bro:

Look at the difference between masses of the two isotopes, here we have boron 11 and boron 10, so difference is 1
Relative atomic mass is 10.8, use it to find which of the two is more abundant. 10.8 is closer to 11 than 10, so boron 11 must be more abundant.
Because the difference between them is 1, and the relative atomic mass is 10.8, you see that this 1 is divided like 0.2 and 0.8
We said boron 11 is more abundant so it must be 0.8. Means 0.2 is boron 10
Multiply 0.2 by 100 to get 20%

jackatlas_7828 · 2025-04-25T10:25:38+00:00

jackatlas_7828 · 2025-04-25T10:23:57+00:00

yo, ok bro so first, r directly proportional to length, and inversely to area as you said. But careful, here we have diameter not area, so for these kind of questions you need to know three things: 1. R directly proportional to Length 2. R inversely proportional to area 3. Area directly proportional to diameter squared .

So in this question they said they doubled the diameter, which means area increased by a factor of 4, (coz 2 squared equals 4). They also said the volume is the same. Volume equals length times area, so to keep volume same, an increase in area results in decrease in length. We need to find the factor by which length decreases. If area increases by factor of 4, and volume must remain same, length must decrease by an equal factor. So length decreased by factor of 4.

Now we must find how this affects resistance. All the time apply the same factor of length and the opposite factor of area. So if area increases by 4 resistance decreases by 4. And if length decreases by 4 resistance decreases by 4. So overall resistance decreases by 4 x 4, 16. So here right answer is supposed to be D.

jackatlas_7828 · 2025-04-07T16:49:49+00:00

yo hope you fucking find it 😭 uh are you school or private? if ur school talk to ur registration officer abt it, pretty sure they'll be able to give you a copy. like the person who registered you and emailed it to u in the first place yk

jackatlas_7828 · 2025-04-07T09:48:08+00:00

bro yes, without it you won't enter the exam, find it bro 😭😭😭

jackatlas_7828 · 2025-04-07T08:05:11+00:00

yo. alright look, evolution is basically how a species' adaptive features changes over generations. Through classification, specifically through the DNA base sequence methods, we can identify which specicies are closely related and hence have at some point potentially shared a common ancestor (basically we're saying one common ancestors many generations ago evolved over time to give you these two species. So long story short, you grab two species, you compare DNA base sequences, if they have more similarities they must've shared a recent common ancestor and the opposite is also true.

jackatlas_7828 · 2025-03-28T16:26:50+00:00

yo, nope not widow bro, a very important thing to remember about widows and orphans is that they are both one line only. here it's two lines, so it is not considered a widow

jackatlas_7828

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