physics.....TOUGH QUESTION

[zxcvbnm]

it's for phase difference...you know, if two points on a wave are in phase, their phase difference is given by n(lambda)....and if they're out of phase, their phase difference is given by (2n+1)lambda/2...where lambda is the wavelength...

[tmisterr]

Could you illustrate that on the graph. I am still not clear. Phy is not too good a subject of mine

ohh can't illustrate now, kinda busy...but let me try elaborate. look at the graph, draw a line from the origin to A, another from the origin to B, another from the origin to C, and another from the origin to D. as you can see, the line from the origin to C has the highest gradient right? so this means change in y(I)/change in x(V) is greatest right? since resistance is the reciprocal of this I/V that is V/I,  it will be smallest if I/V is greatest thus C.

[nid404]

ohkay thanks...i get it now

[superduper2009]

guys..one question..
when a metal is heated.. i.e. it's temperature increases... it's resistance decreases right???

[halosh92]

guys..one question..
when a metal is heated.. i.e. it's temperature increases... it's resistance decreases right???

no no!!!!
when temp increase resistance increase because more energy more collisions so its more difficult for current to pass.
thats for all metals
ure case happens only with thermistors 

[yinyang]

can someone explain Q25 (p12 nov 2009)

[astarmathsandphysics]

sinx=nw/d
d=0.001/300=3.3*10^-6
w=450*10^-9
sin x =n*5/37<1
n<37/5=7.4
n=7