Home
Class 12
PHYSICS
A hot liquid kept in a breaker cools fro...

A hot liquid kept in a breaker cools from `80^(@)C` to `70^(@)C` in two minutes. If the surrounding temperature is `30^(@)C`, then the time of cooling of the same liquid from `60^(@)C` to `50^(@)C` is :

A

240 s

B

480 s

C

360 s

D

216 s.

Text Solution

Verified by Experts

The correct Answer is:
D
According to Newton.s law of cooling
`(theta_(1)-theta_(2))/(t)=k[(theta_(1)+theta_(2))/(2)-theta_(0)]`
`:.(80-70)/(2)=k[75-30]` . . . (i)
`(60-50)/(t)=k[55-30]` . . . (ii)
Dividing (i) by (ii) `t/2=(45)/(25)rArrt=(18)/(5)=3*6" min = 216 seconds"`
So correct choice is (d).
Promotional Banner

Topper's Solved these Questions

  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Multiple Choice Questions (Level - II)|49 Videos

  • TRANSFERENCE OF HEAT

    MODERN PUBLICATION|Exercise Multiple Choice Questions (Level - III) Questions From AIEEE/JEE Examination)|5 Videos

  • SOLIDS & SEMICONDUCTOR DEVICES

    MODERN PUBLICATION|Exercise Revision Test|28 Videos

  • UNIFORM CIRCULAR MOTION

    MODERN PUBLICATION|Exercise Revision Test |57 Videos

Similar Questions

Explore conceptually related problems

A pan filled with hot food cools from 94^(@) C " to " 86^(@) C in 2 minutes when the room temperature is at 20^(@) C . How long will it take to cool from 71^(@) C " to " 69^(@) C ?

A pan filled with hot food cools form 94^(@)C to 86^(@)C in 2 minutes . When the roo temperature is 20^(@)C . How long will it cool from 74^(@)C to 66^(@)C ?

A body cools from 80^(@)C to 70^(@)C in 6 minutes Under the saame external conditions to cool from 60^(@)C to 50^(@)C it will take

A body cools from 80^(@)C to 50^(@) C in 5 minutes. Calculate the time it takes to cool from 60^(@)C to 30^(@)C . The temperature of the surroundings is 20^(@)C

Hot water cools from 60^(@)C to 50^(@)C in the first 10 minutes and to 42^(@)C in the next 10 minutes Then the temperature of the surrounding is