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Hi friends, i am sorry but i was unable to see his yars iit paper. Can any one post the exact figure. But still i want to make some points on the basis of above discusions
i) If it a cavity then we cannot assum charge inside it unless it is given that there are charges kept there.
ii) To find electric field in the cavity we will take a surface insied the cavity. A surface outside the cavity calculate flux E.ds at points which are not inside cavity.
iii)if cavity is present at the center and rest charge is arranged uniformaly around it then field inside it is zero.
iv)if cavity is not present at the center then electric field inside cavity will b non-zero, but i think it will be non-uniform in general

Let me approch the question from very basic. If we change earth's orbital radius from r o kr, th energy reachinf eart will change from E to E/k^2. As this is also equal to energy emited by earth which is proportional to T^4 so the temp will change from T to T/sqrt(k). As present temp of earh is about 280K to make it 275K k should br (280/275)^2 which is about 1.037. So to decrease temperatur from 280 to 275 earth's radius should increase by about 3.7%

right point raised by v k vashistha, please tell whether any magneticfield exist or not

Good answer indian army

Right answer is indeed 3s+sqrt(2fs)*t. Nigitha i think u made a typing mistake

Hi pari gupta, well i am not very sure what do you maen by space average velovity, but in general while averaging space averaging of any function f is

space av (f)= (_{[0 ]}

^{[x ]} f.dx)/x

time av (f)= (_{[0 ]}

^{[t ]} f.dt)/t

So if we aply same definition to velocity then

space av (v)= (_{[0 ]}

^{[x ]} sqrt(2gx).dx)/x=2v/3

while time average=v/2

So answer should be 4/3

Can you post the exact question

So consider a spring of conslant k and legth l which is cut inti two parts of length l/3 and 2l/3 with constants k1 and k2.

From 1) k1/k2=2

As there resultant constant is k when they are in series from third 1/k = 1/k1+1/k2
solving these we get
k1=3k
k2=1.5k

Good Answer KAB

The equation of continuty says that for any position of tap the volume flow rate of water is constant through out the pipe. Thus if for a given position it is 100ml per minute it will be same at all points in the pipe and for another position it may be 150ml per minute again for all positions of pipe. But it does not says that if in first position the flow rate was 100 ml per minute, it will remain so in second position as well

Good work aditya. The answer will be 0.5*6/7 meters

Even I am not sure but It will always be a multiple of some fixed number (As transformers step up and down all the vpltages) But why that number is 11 only i think thats just a convention

Good but if you want to know the fundamental behind it. No one exactly knows. We know it just by observation

If you make a figure of this problem you wil get i=2r and sin(i)=d/r
So sin(r) = sin(i/2) =sqrt((1-cos(i))/2)
Condition

n*Sqrt((1-sqrt(1-d^2/r^2))/2) =d/r

Good answer Indian_army