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A spherical rain drop evaporates at a ra...

A spherical rain drop evaporates at a rate proportional to its surface area at any instant `tdot` The differential equation giving the rate of change of the radius of the rain drop is _____

Text Solution

Verified by Experts

The correct Answer is:
`((dr)/dt=-lambda)`
Since, Rate of change of volume `propto` surface area
`rArr (dV)/dt propto SA`
`rArr 4pir^(2)cdot (dr)/dt=-lambda4pir^(2)`
`(dr)/dt=-lambda` is required differential equation.
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