A spherical raindrop evaporates at a rate proportional to its surface area. The differential equation involving the rate of change of its radius $r$ with time $t$ is ... (where $k$ is a positive constant)
- A$\frac{dr}{dt} + k = 0$
- B$\frac{dr}{dt} - k = 0$
- C$\frac{dr}{dt} + kr = 0$
- D$\frac{dr}{dt} - kr = 0$
Explore More
Similar Questions
$\vec{A}$ and $\vec{B}$ are two non-zero vectors inclined at an angle $\theta$. $\hat{a}$ and $\hat{b}$ are unit vectors along $\vec{A}$ and $\vec{B}$ respectively. The component of $\vec{A}$ in the direction of $\vec{B}$ is
If the velocity of the electron in Bohr's first orbit is $2.19 \times 10^6 \text{ m s}^{-1}$, calculate the de Broglie wavelength associated with it. [$h = 6.626 \times 10^{-34} \text{ J s}$ and mass of electron = $9.10938 \times 10^{-31} \text{ kg}$] (in $\text{ pm}$)
DifficultMHT CET 2026
View SolutionIn a regular octagon $ABCDEFGH$ with center $O$,what is the sum of $\overrightarrow{ AB }+\overrightarrow{ AC }+\overrightarrow{ AD }+\overrightarrow{ AE }+\overrightarrow{ AF }+\overrightarrow{ AG }+\overrightarrow{ AH }$ if $\overrightarrow{ AO }=2 \hat{ i }+3 \hat{ j }-4 \hat{ k }$?
DifficultJEE MAIN 2021
View SolutionA body cools from $100^\circ C$ to $60^\circ C$ in $20$ minutes, the temperature of the surroundings being $20^\circ C$. The total time taken (in minutes) for the body to cool down to $40^\circ C$ is ...
DifficultMHT CET 2026
View SolutionIf two vectors $2\hat{i} + 3\hat{j} - \hat{k}$ and $-4\hat{i} - 6\hat{j} + \lambda\hat{k}$ are parallel to each other,then the value of $\lambda$ is:
Medium
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo