Physics · Mechanical Properties of Matter

JEE Main 2026 — 23 January, Evening Shift — Question 44

A ball of radius r and density ρ\rho dropped through a viscous liquid of density σ\sigma and viscosity η\eta attains its terminal velocity at time t , given by t=Aρarbηcσd\mathrm{t}=\mathrm{A} \rho^{\mathrm{a}} \mathrm{r}^{\mathrm{b}} \eta^{\mathrm{c}} \sigma^{\mathrm{d}}, where A is a constant and a,bc\mathrm{a}, \mathrm{b} \mathrm{c} and d are integers. The value of b+ca+d\frac{b+c}{a+d} is ____\_\_\_\_ .

Answer: 1

Numerical answer — enter this value.

Step-by-step solution

T=(ML−3)aLb(ML−1 T−1)c(ML−3)d\mathrm{T}=\left(\mathrm{ML}^{-3}\right)^{\mathrm{a}} \mathrm{L}^{\mathrm{b}}\left(\mathrm{ML}^{-1} \mathrm{~T}^{-1}\right)^{\mathrm{c}}\left(\mathrm{ML}^{-3}\right)^{\mathrm{d}} T=Ma+c+dL−3a−c−sd+bT−c\mathrm{T}=\mathrm{M}^{\mathrm{a}+\mathrm{c}+\mathrm{d}} \mathrm{L}^{-3 \mathrm{a}-\mathrm{c}-\mathrm{s} \mathrm{d}+\mathrm{b}} \mathrm{T}^{-\mathrm{c}} on comparing c=−1;a+c+d=0;−3a−c−3 d+b=0\mathrm{c}=-1 ; \mathrm{a}+\mathrm{c}+\mathrm{d}=0 ;-3 \mathrm{a}-\mathrm{c}-3 \mathrm{~d}+\mathrm{b}=0 b=2;a+d=1\mathrm{b}=2 ; \mathrm{a}+\mathrm{d}=1 b+c=1\mathrm{b}+\mathrm{c}=1

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Physics
Chapter
Mechanical Properties of Matter
Topic
Viscosity
A ball of radius r and density ρ dropped through a viscous liquid of… | JEE Main 2026 PYQ with Solution · DhiX AI