JEE Main 2015PhysicsUnits and DimensionsMediumMCQ

JEE Main 2015Units and Dimensions Question with Solution

JEE Main 2015 (11 Apr Online)

Question

A beaker contains a fluid of density ρkgm3 , specific heat SJkgoC and viscosity η . The beaker is filled up to height h. To estimate the rate of heat transfer per unit area Q˙A by convection when beaker is put on a hot plate, a student proposes that it should depend on η , SΔθh and 1ρg when Δθ ( inoC ) is the difference in the temperature between the bottom and top of the fluid. In that situation the correct option for Q˙A is:

Choose an option

Show full solutionCorrect option: A
Correct answer
ASΔθhη

Step-by-step explanation

QA=ηxsθhy1ρgz . . . (1)

QA=MT-3,η=ML-1T-1

sθh=LT-2,1ρg=M-1L2T2

MT-3=MxL-xT-xLyT-2yM-2L2zT2z

MT-3=Mx-zL-x+y+2zT-x-2y+2z

So 1=x-z . . . (2)

-x+y+2z=0. . . (3)

-x-2y+2z=-3. . . (4)

from 2, 3, 4

x=1, y=1, z=0from (1)

so QA=η sθh

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Units and Dimensions chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2015, covering the Units and Dimensions chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.