• 6 karma
Getting energy from water. Read this in a book
In water, H2O, some times we may find a heavier isotope of Hydrogen, called Deuterium. (Atomic mass of normal Hydrogen atom = 1, of Deuterium = 2). It has been known for long that two Deuterium atoms can be fused to form an atom of Helium. Thats what happens in the sun and other stars. 1kg of Deuterium provides as much energy as 14 million kgs of coal burned. And, our oceans have enough Dueterium as part of water to last mankind for 30 million years (if mankind survives that long).
However, to fuse two deuterium atoms, we need a temperature of 200 million degree Celsius. At this high temperature, everything converts into plasma, even the installation in which such a conversion is attempted. Hence, it isnt viable to store plasma in a container, and hence it is packed using magnetic fields. However, plasma always seeks a crack in the magnetic fields, and finding one, breaks free and the deuterium flies off in all directions and is lost.
Soviet scientists had designed and built a series of installations called TOKAMAK to provide high temperatures. However, the maximum they can go upto is 20 million degrees, just 10% of what we require.
Hence, scientists have found another way. They take a small granule of ice of water having deuterium. A laser beam is directed at it. This heats it to a very high temperature. But before it melts to form water, the deuterium atoms in it start fusing and realease energy. This causes an explosion, which realeases the energy, though in very small quatities. In order to get a sizable amount of energy, 20 granules of ice should be exploded per second.
This energy is used to heat liquid lithium, which transmits heat to water (normal). The water turns to steam and is directed to a turbine which generates electricity.
The use of this method, (called thermonuclear energy) not only produces a great deal of energy, but is also non-polluting.
Hydrgen is a highly combustible fuel. Also, using hydrogen is economically viable, as huge quantities of it are present in the seas and in crude oil. Also, hydrogen burns to form water, and hence hydrogen is the cleanest fuel. At present, hydrogen is extracted from crude oil, which is an expensive process, and produces very little H2. So instead, electrolysis can be used to extract H2 from the seas. However, this would require a lot of electricity itself, which can only be provided by a nuclear power station.
So, scientists have come up with a design of a floating nuclear power station on the seas and oceans. All electricity produced would be used to extract hydrogen, which would be pumped to the mainland through pipelines. This H2 would then be converted to liquid before being distributed to the final consumers. It may give two benefits. Burning liquid hydrogen will give power, and also forms water, the purest water on earth. So, both power and water needs of people are satisfied.
However, proper storage of hydrogen gas is necessary, since, if kept in the open, it will evaporate, and if tightly shut, it may craete pressure and explode. So, the containers must be open only just enough to avoid an explosion, and yet retain as much hydrogen as possible.

What about the hybrid cars which were supposed to have hit nations in order to cut-down on dependency on Oil n natural gas.
Also, I remember reading article in TOI which mentioned that technology to extract energy from Water existed way back in 70-80's and a certain german engineer had worked extensively in this area but the industry big-wigs BP,Shell had more muscle power to nip the bud....reason-moolah would be lost coz what about the investment they had made in refineries and the oil which they produce which does become less than its worth!! Sounds cynical.

Anyway, whoever said 3rd world war would be fought for water might have seen this coming....Any comments.
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The solution to Q 17 is absolute BS......laughable. For all my money my score should be 60.67 and not 59.33, would have been very comforting to have a 60+ score.
Sectional scores and Appr %iles :-
VA/RC --> 27.33 %ile = 99.3
QA --> 10.33 %ile = 94
DI --> 21.67 %ile = 92.5
Overall --> 59.33 with %ile = 99.4 and AIR 66. Feels good to have a good %ile after many "not so inspiring" performances in the TIME mocks. I really needed a confidence booster and this mock has been just that. I am pretty pleased that in VA/RC I am finally where I belong, 99.3+ which should give me some hope to get past 99.5 in CAT.
Somehow I dont yet figure in the Toppers List inspite of clearing all cutoffs but then I havent seen even a single guy from Blore in the Toppers list. Maybe they havent yet updated the Toppers List with the Blore results.......as per the current list I should be looking at a rank of around 30-35.
ATB for the next one.
Edit: I Can now see my name at the 49th place in the Toppers List.:)

Good Score Orca,

Another beating taken by me in this Mock cat....Here is the performance. Was struggling with QA and RC...anyway my overall score is 41.4. Cleared only DI cut-off.

ATB for mC-5.
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For the I question : It was given that A is a number such a way that A+2 is exactly divisible by 15,16,17,18 and 19. Hence A is lcm of 15,16,17,18 and 19 -- 2. Which comes out to be 15504 -- 2 = 15502 = 2 * 7751. Now B is product of 15, 16, 17, 18 and 19. HCF for the 2 numbers is 2. Hence 2 is the answer

We may not have to calculate at all.....If lcm of 15,16,17,18,19 be K then A=K-2
and B=K is the other number.
Obviously the HCF of A and B also must be present in their difference A-B i.e K-(K-2).
Hence the HCF 2 (as K is definitely even and so is K-2)

i guess we are sailing the same boat.my scores are an almost replica of ures(xcept for QA where uve scored heavily).my neta ttempts being the same as you,ie 58 and my relative scores are:
but wen i saw ppl scoring in 60's and dat tooo very easily..i was really taken aback. didnt turn out a good week for me either.feeling slitely low after that.
but i guess everyone passes thru dat phase once a while in CAT preparation. i have been getting percentiles ranging frm 97-99 in all FLT's and MOCKS but somehow screwed up the last one.
lets see whats in store for me dis sunday.
all the best!
ps: wat ru doing to improve da no of attempts? mine just dnt cross 70-75

Very true...one can get down and feel out at times like these.
To improve attempts : Guess need more practise....to identify better questions and
at the same time handle stress....anything missing from the list ?
Easier said than done though!!:smile:

ps : how were you managing 97-99 % scores in FLT's n earlier mocks? Sure can
use some gyan here.
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Hi Junta,
Thought of asking people who are taking tests of 2 or more institutes ...
Kindly post your views about the level of difficulty of each of these tests.
Heard Aimcats are tougher than simcat and cl mocks...any other institutes...like PT,Career Forum??
On a scale of 1 to 5 ( 1- easiest, 5 toughest)
How would you rate each of them?
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A much needed wake-up call........
Ended up at overall score = 42.00 and %ile of 88.5. Didnt clear even a single cutoff, not even VA/RC, just abt managed to hit 90%ile here.........

The cutoffs here are definitely on the higher side compared to TIME and do appear more realistic, good that I got a sound beating in my first CL mock. All the junta has happily cracked 20+ in DI and I was kinda pleased with a score of 17 which was brought down to 15 because of the key changes. Net result :- 70%ile in DI

Lots of catching up to do.......its been a bad week, screwed up both TIME and CL mocks.
ATB for the next one.

Me too screw*d my chances big big time with sad performances in RC-VA/DI
Even though RC/DI were on the easier side...RC-VA definitely not CAT std and here
i find self not clearing cut-offs

Section/Attempts/Correct /Net

Rc-VA 23 / 18 / 16.6 sad.

DI 17 /10 / 8.3 very sad.

QA 18 / 16 / 17.33 good.

Net 58 / 44 / 42.4 ---

Any suggestions?? Good luck to all.
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I used to have this hobby of collecting kites back when i was a lil boy...
would catch all kinds - even if they were torn or useless.
Liked to collect them for their colours and designs and shapes....extent of madness was that i would sometimes pull the string of a kite flying by and snap it with my "maanja" so that i could run down the apartment block and collect it from where ever it landed...mean me .
Had a whole stack of it.....nearly 200 odd kites....well thats that.:smile:

2.A school boy starts at a particular time from his house.After travelling fro 1/3 rd of the distance he is at the railway station at 7:25 and after travelling 3/4 th of the remainging distance he is at some other place at 7:30.Now at what time did he start from his house and at what time will he reach his school?

Dude...not a good idea to spam threads out of sheer desperation...post in relevant threads.
solution posted here for same problem
Pleasee solve these questions:

4.A train blows a siren one hour after starting from the station. After that it travels at 3/5th of its speed it reaches the next station 2 hours behind schedule. If it had a problem 50 miles farther from the previous case,it would have reached 40 minutes sooner. Find the distance between the two stations .

5.Mr. ANYMAN left ANYTOWN by car to attend a wedding at ANYCITY. He had been driving for exactly two hours when the car got punctured. It took his driver exactly ten minutes to change the wheel. In order to play safe they covered the remaining distance at a speed of 30 mph. consequently, Mr. ANYMAN was at wedding half an-hour behind schedule. Had the car got the puncture only 30 miles later , I would have been only FIFTEEN minutes late he told the driver . How Far is ANYCITY from ANYTOWN.

Questions of these types have been solved previously but here goes my solution anyways....hope i won't be sued for plagiarizing the diagram as follows : )

Sol 4 : X-------------------M----------N--------------------Y

start ----> end

M is 1 hour away from start X after which the train starts travelling at 3/5th of speed s = 3s/5

N is point 50 km ahead of M.

Case 1 . X-M-Y stopppage causes delay by 2 hours.

Case 2 . X-N-Y stoppage causes delay by 1 hour 20 mins ( 40 mins sooner).

Clearly difference in case timings is due to MN being travelled at different speeds i .e.

3s/5 rather than at s itself causing a delay of 40 mins.

Therefore, 50/(3s/5) - 50/s = 40 / 60 or 50 *(5/3s - 1/s) = 2/3 or s =50 mph

And distance can be found from the fact that travelling MY at 3s/5 causes delay by 2 hours

i.e. x/30 - x/50 = 2 or x =150 miles.

Hence total distance = 50(1hour travel) + 150 = 200 miles.

Sol 5 : In this case too saving of 15 mins happens due to travelling of 30 miles
at speed 30 mph which is lesser than actual speed s (else there won't be a delay...right)

Therefore 30(1/30-1/s)=1/4
s = 40 mph

Therefore for 2 hours they cover 80 miles and let rest of distance be x.

Again the delay of 30 mins is causesd by
- 10 mins of tyre change
- by travelling distance x at 30 miles rather than 40 miles.

Therefore x/30 - x/40 = 20/60 or x/120 = 1/3 or x = 40 miles

Total distance = 80 + x =120 miles.
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A school boy starts at a particular time from his house.After

travelling fro 1/3 rd of the distance he is at the railway station at

7:25 and after travelling 3/4 th of the remainging distance he is at

some other place at 7:30.Now at what time did he start from his house

and at what time will he reach his school?

After travelling 1/3rd distance - 2/3rd distance is left say 2/3*D.
3/4th of 2/3*D is nothing but D/2 which the lad covers in 5 mins.
Therfore the whole distance is covered in 10 mins.

Assuming speed remains constant throughout...1/3*D is covered in 1/3rd of 10 mins.

i..e. 3 mins 20 sec...Boy started at 7:21:40 ( 7:25 minus time to cover 1/3rd distance) morning and reaches at 7:31:40.
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