106sorry din see akshay posted.....
MORE ADDED1.A beaker containing water is balanced on a pan of a common balance.A solid of specific gravity 1 and mass 5 g is tied to the arm of the balance and immersed in the water of the beaker.The scale pan with the beaker:
a)goes up
b)goes down
c)remains unchanged
d)none
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75 Answers
10611. cos x=√(1-sin 2x)
cosx = √(cosx-sinx)2
=> cosx = |cosx-sinx|
CASE I.. cosx > sinx
cosx = cosx - sinx
=> sinx = 0
=> x=0, 2pi
CASE II .. cosx < sinx
=> cosx = -cosx + sinx
=> sinx = 2cosx
=> tanx = 2
we have one solution for this in (0, pi/2) (other solution wont be possible as condition is sinx> cosx
So total no. of solutions = 3
btw yeh question kaun se saal ka hai?
1akshay the solution is important be it a photo,manuscript,painting.. anything will do.
14.11Na23 is the more stable isotope of NA.what is the process by which 11Na24can undergo radioactive decay:
a)alpha emission
b)beta emission
c)beta + emission
d)K-electron capture
13Arka, Bhai Qn(s) ko number kar do....Confusion hota hai.
Fr the 1st one, The Balance....won't it be (c)...?
Fr the last one, yeah Saket gave the reac.n...Iron is reduced, so Al is the reducing agent.
21alumino-thermite reaction-Fe2O3 + 2 Al → 2 Fe + Al2O3
and is the answer for the beaker and balance question (a)???
21arka, i thought ore heated in presence of air is called roasting?
16.in alumino thermite process,Al is
a)reducing agent
b)oxidising agent
c)solder
d)flux
ans-a.how?
1@arka in tht radioactivity question answer is B.........as far as i think :)
15.smelting is:isnt smelting simply redn by coke?
a)ore heated in absence of air
b)ore is cold
c)ore heated in presence of air
d)ore is melted
ans given-c
1soham,in electron capture,an electron from the surrounding shells is captured by the nucleus.K electron capture happens when that electron is captureed from the K shell
13As for Smelting, it is not only by Coke, but reduction by other agents is also termed as smelting.
So, fr tht Qn, all the options seem 2b wrong,, so no need 2 look fr a correct answer amongst them. [3]
1Q 3>The rate constant of the rxn : H2O2-->2H20 +02 IS 3*10^-3 per minute. At what conc os hydrogen peroxide the rate of rxn will be 2*10^- M per sec
39Well the answer doesn't match completely with any of the options(as per what this gives)...only -1 < m < 3 matches partly with the answer.
Could've done it quicker by using -b2a > or < root.
106@pritish: dont take me wrong... ive been trying that as well but gave up since i got none of the options...
39I was just about to edit...but atleast I didn't wait for someone to answer and then conveniently point out the mistake in their answer :P
39f(-2) > 0 and f(4) > 0. Use these to get inequalities in quadratic m.
CASE I : f(-2) > 0
4 + 4m + m2 - 1 > 0
or m2 + 4m + 3 > 0
D = 16 - 12 = 4
m = -4 ± 22
= -1, -3
(m + 1)(m + 3) > 0
m → (-∞, -3) U (-1, ∞)
CASE II : f(4) > 0
16 - 8m + m2 - 1 > 0
or
m2 - 8m + 15 > 0
=> m2 - 3m - 5m + 15 > 0
=> (m - 5)(m - 3) > 0
m → (-∞ , 3) U (5, ∞)
Taking intersection of both cases,
m → (-1 , 3) U (5, ∞)
12.the values of m such that both roots of x2-2mx+m2-1=0 are greater than -2 and less than 4 lie in the interval:
a)m>3
b)-1
1arka i thought in this manner
in physics inelastic means a material that in colloquial terms is actually "highly elastic" like rubber and similar stuff that regain their initial form after being pulled...
that means the change in length is infinite so Young's modulus is zero..
hope this has made this clear
1cud u explain the realtion between e and y in more details sridhar?
wat do u mean by e?hopefully not coeff of restitution in collisions