IIT JEE , AIEEE Forum - Physics , General

soumidattaiitd

how to find dimension of any new quantity which is not fundamental?i am just starting woth jee preparation..

karthik_abiram

hi,

just change all the derived quantities{i.e other than fundamental quantities}

into fundamental quantities,and then apply the dimensions and simplify to get the dimension of the required quantity..........

is this wat u wanted or any thing else?

edison

Karthik is right as far as your query is concernerd.

For better understanding u can post some unsolved problem on units and dimensions.

iitkgp_bipin

I will explain with the help of an example.

Force of attraction between two bodies is given by :

F = Gm₁m₂/r² , to fond the dimension of G.

G = Fr²/m₁m₂

As force is (mass)x(acceleration0 its dimension is [M][a] = (M)(LT^-2)

[G] = [Fr²/m₁m₂] = [F][r²]/[m₁][m₂]

[G] = (MLT^--2)(L²)/{(M)(M)}

[G] = M^-1L³T^-2

Write down the dimensions of the quantities in terms of base quantities and simply do multiplication and division of them.

jaysunantony

Sir,
while finding the pitch of a Scre Gauge.............what if we stated exactly from
zero on the Main Scale and after fve rtations......the Main Scale reads 5.4mm
or
smthng like that............

then is the pitch 1mm or [5.4/5] mm..................Please reply....

Avinash_Bhat

Hey, Jaysun.. It's (5.4 / 5)mm as : pitch = distance moved / no. of rotations given..

And.. Soumi,

For all those quantities which are not fundamental, directly or indirectly they will have a relation with those fundamentals qts.

Eg : Velocity = Displacement / Time

= [L] / [T]

And like this, all those simple quantities may be dimensionalised from which we can find those quantities like 'G' as our Bipin Sir has done...

sjkalyan

if u r an inter 1st yr student id suggest u refer some gud book or else the inter 1st year text book

there a quite a few examples & jst work them out

then ull find how simple they are

ankush_foru

hello..
can anbody help me out for the problems on optics?????
plz reply its urgent...

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