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### IITJEE 2011 tips and tricks

1. If yo are trying to attempt for IITJEE just after your board exams then try not to pick up the new topic which you haven’t studied yet.

2. If your main aim is IIT JEE then you should try to read the basics for the chapters you have already prepared, as their wouldn’t be even a single question which you would find in the books,it’s the basics that help while solving the examination.

3. Try to go through the compendiums once, they may come in handy while solving the examination.

4. IIT JEE is not like a war against time,their is plenty of time if you solve the paper systematically.

5. Never try to go for all the questions,if you are sure of 60% paper then it’s pretty enough to get a good rank in IIT JEE,coz for the year 2010 the cut off was around 185...

6. Their is surely going to be lot of questions from cyclic compounds in chemistry so be sure to do them thoroughly,chemistry is the most scoring part in the paper

7. Try to give about 45 minutes to chemistry,55 minutes to physics and the rest to mathematics and also spare 5 minutes in the end to recheck.

8. Don’t stick to one question if you think that the question of 3 marks would take more then 5 minutes then leave it and try at the end ,also if you are not able to solve the question move to the next one,not waste much time on single question.

9. Try to mark the answers simultaneously when you are solving the paper,though many students do mark the answers in the end so plan your time accordingly.

source : iitjeeclub.com

### Heat and thermodynamics solved questions

Question-1.Let A & B are two sample of ideal gases of equal mole .let T be the temperature of both the gas Let EA and EB are there total energy respectively .Let MA and MB are these respective molecular mass .which of these is true

a,EA > EB

b,EA < EB

c,EA =EB

d,none of these
Solution:1

EA = 3/2 nRT

EB = 3/2 nRT

;EA =EB

Question-2. The velocities of the molecules are v, 2v, 3v, 4v & 5v. The rms speed will be

a,11v

b,v(11)1/2

c, v

d, 3.3v

Solution:2

Vrms= (∑ V2 / N)1/2

= [(V2 + 4V2 + 9V2 + 16V2 + 25V2)/5]1/2

=v(11)1/2

Question-3. What is true of Isothermal Process

a, ΔT >0

b, ΔU=0

c ΔQ=ΔW

d PV=constants

Solution-3:

In an Isothermal Process

Temperature remains constant ΔT =0

Since Internal energy depends on the temperature

ΔU=0
From first law of Thermodynamics

ΔU=ΔQ-ΔW

Since ΔU=0

ΔQ=ΔW

Also PV=nRT

As T is constant

PV= constant

Question-.4 Two absolute scales A and B have triple points of water defined as 200A and 350A. what is the relation between TA and TB

Solution-4
Given that on absolute scale
Triple point of water on scale A = 200 A
Triple point of water on scale B = 350 B
Also, triple point of water on Kelvin scale = 273.16 K
Now temperature on scale A and on scale B is equivalent to 273.16 K on absolute temperature scale.
Thus, value of one degree on absolute scale A = (273.16/200) K
Or,
Value of temperature TA on absolute scale A = (273.16XTA)/200
Similarly value of temperature TB on absolute scale B = (273.16XTB)/350
Since TA and TB represent the same temperature
273.16×TA/200 = 273.16×TB/350
Or, TA = 200TB/350 = 4TB/ 7

Question 5: A gas is contained in a cylinder with a moveable piston on which a heavy block is placed. Suppose the region outside the chamber is evacuated and the total mass of the block and the movable piston is 102 kg. When 2140 J of heat flows into the gas, the internal energy of the gas increases by 1580 J. What is the distance s through which the piston rises?
Solution:5
Total heat supplied =Workdone + Change in internal energy
So work done=2140-1580=560 J
Let s be the distance moved then

the workdone is given by =Fs

Fs=560

s=560/F

=560/102*10

s=.54 m

### Rotation with constant angular acceleration

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