Question

calculate the energy spent on spraying a drop of mercury of 1 cm radius into 10^6 droplets all of same radius. surface tension of mercury is 0.035N/m

Answer 1

Answer:

ANS : .Energy spent on spraying =$4.3542*10^{-4}J$

Explanation:

Given:

• Radius of mercury = 1cm initially ;
• split into $10^{6}$ drops ;

Thus, volume is conserved.

i.e ,

$\frac{4}{3} \pi R_{o}^{3} = 10^{6}*\frac{4}{3} \pi R_{n}^{3}\\R_{n}=\frac{R_{o}}{10^{2}} = \frac{1cm}{100} = 0.01 cm$

• Energy of a droplet = $T$Δ$A$

Where ,

• T is the surface tension
• ΔA is the change in area

Initial energy $E_{i} = T*A_{i}\\= 0.0035 * 4 *\pi *0.01^{2}\\=4.398*10^{-6}J$

Final energy $E_{f}=10^{6}*T*A_{f}\\=10^{6}*0.0035*4*\pi *(0.0001)^2\\=4.39823*10^{-4}$

∴  .Energy spent on spraying = $=E_{f}-E{i}\\=(439.823-4.39823)*10^{-6}\\=4.3542*10^{-4}J$

ANS : .Energy spent on spraying =$4.3542*10^{-4}J$