Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

a body takes 4 minutes to cool from 62°c to 58°c, surrounding temperature being 30°c. the time taken for body to cool from 46°c to 44°c will be?
Asked by sbtech357 | 23 Jul, 2018, 02:49: PM
answered-by-expert Expert Answer
Assuming that the newton's law of cooling stands true for the given change in temperatures.
We first find the value of 'k'

begin mathsize 12px style dT over dt equals space straight k space left parenthesis straight T minus straight T subscript straight s right parenthesis
dT space equals space change space in space temperature
dt equals space change space in space time
straight k equals space constant space
straight T subscript straight s equals space surrounding space temperature
Taking space the space average space of space two space temperatures
3 over 4 equals straight k space open square brackets fraction numerator 62 plus 58 over denominator 2 end fraction minus 30 close square brackets
3 over 4 straight k equals space left square bracket 30 right square bracket
straight k equals 1 over 40 end style
 
Using this value of k we find change in time for second case
 
begin mathsize 12px style 2 over dt equals 1 over 40 open square brackets fraction numerator 46 plus 44 over denominator 2 end fraction minus 30 close square brackets
fraction numerator begin display style 2 end style over denominator begin display style dt end style end fraction equals fraction numerator begin display style 1 end style over denominator begin display style 40 end style end fraction open square brackets 15 close square brackets
dt equals 80 over 15 equals 5.33 space mins
end style
Answered by Abhijeet Mishra | 26 Jul, 2018, 01:16: PM
CBSE 12-science - Physics
Asked by mailtoanjalip2005 | 16 Mar, 2024, 08:22: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by am1954077 | 08 Mar, 2024, 04:57: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by himanshurawat5823 | 08 Mar, 2024, 01:24: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by rohandhawaniya17112006 | 06 Mar, 2024, 03:32: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by shivamtkr7767 | 03 Mar, 2024, 12:45: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by sahupranav2006 | 02 Mar, 2024, 03:37: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by rishabhverma895334 | 01 Mar, 2024, 07:24: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by writetoakashyadav | 28 Feb, 2024, 07:41: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by nikstar1456 | 14 Feb, 2024, 01:09: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
Get Latest Study Material for Academic year 24-25 Click here
×