IIT 2000

RON... I M VERY SURE....BUT THE FREQUENCY IS DIRECTLY PROP..TO THE KINECTIC ENERGY OF A MOLECULE ...ie 3RT/M* 0.5*M......PROP...TO ITS TEMP.....IF THIS LOGIC IR RITE THEN....REASON IS FALSE

Ans given is D..
i.e Assertion is False, Reason is true.

assertion is false becuase the above would happen if volume was also constant.

reason.

collision frequency = root mean velocity/mean free path.
propotional to root of temp.

and impact= Δp/Δt= 2mv/Δt which is also propotional to root of temp.

AT CONSTANT VOLUME

P directly proportional to T .........................(1)

U_rms = √(3RTM)
that is U_rms is directly proportional to √T..

Collision frequency is directly proportional to U_rms hence to √T.

So on increasing collision pressure frequency increases,[increaing pressure means increasing temp. from 1]

HENCE ANS IS (A)

even i thought it would be (A) Manmay..

i guess fiitjee has given the ans wrong.

YA THAT'S RITE................