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When 8 droplets of water of radius 1 mm each combine into one, then the energy evolved is approximately equal to 7 xx 10^(-6)J. Find the value of x.

Answer» <html><body><p></p>Solution :`S=0.07 N//m, r=<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a> mm =1 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 10^(-3)m` <br/> Let R=radius of big drop `<a href="https://interviewquestions.tuteehub.com/tag/4-311707" style="font-weight:bold;" target="_blank" title="Click to know more about 4">4</a>/3 pi R^(3)=8 xx 4/3 <a href="https://interviewquestions.tuteehub.com/tag/pir-591537" style="font-weight:bold;" target="_blank" title="Click to know more about PIR">PIR</a>^(3)` <br/> `R=2r =2 xx 10^(-3)m` <br/> Surface area of bigger drop `=4piR^(2)` <br/> `=4pi xx (2 xx 10^(-3))^(2)` <br/> `=4pi xx 4 xx 10^(-6)m^(2)` <br/> `=16 pi xx 10^(-6) m^(2)` <br/> Surface area of 8 small drops `=8 xx 4pi xx (1 xx 10^(-3))^(2)` <br/> `=32 pi xx 10^(-6) m^(2)` <br/> `triangleA=` decreases in surface area <br/> `=(32 pi xx 10^(-6) -16pi xx 10^(-6))` <br/> `=16 pi xx 10^(-6) m^(2)` <br/> Energy evolved `="Surface Tesnion "xx " decreases in surface area"` <br/> `=0.06 xx 16pi xx 10^(-6)` <br/> `=0.96 pi xx 10^(-6)J=1pi xx 10^(-6) <a href="https://interviewquestions.tuteehub.com/tag/h-1014193" style="font-weight:bold;" target="_blank" title="Click to know more about H">H</a>`</body></html>


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