#### Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Click to Chat

1800-5470-145

+91 7353221155

CART 0

• 0
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

# A wet porous substance in the open air losses its moisture at a rate proportional to the moisture content. If a sheet hung in the wind loses half of its moisture during the first hour, when will it have lost 95% moisture, weather conditions remaining the same.

Jitender Singh IIT Delhi
7 years ago
Ans:
Let ‘C’ be the moisture content at any time ‘t’
Given:
$\frac{dC}{dt} = aC, a = constant$
C* = Initial moisture
$\int_{C*}^{C*/2}\frac{dC}{C} = \int_{0}^1{}adt$
$(lnC)_{C*}^{C*/2} = (at)_{0}^{1}$
$\Rightarrow a = -ln2$
$\int_{C*}^{.05C*}\frac{dC}{C} = \int_{0}^{t}-ln2.dt$
$\Rightarrow t = \frac{ln20}{ln2} hr$
Thanks & Regards
Jitender Singh
IIT Delhi