Question

Surface tension of soap solution is 1.9 × 10⁻² N/m. The work done to blow a bubble of diameter 2.0 cm is ............ . (A) 17.6 x 10⁻⁶ π J (B) 15.2 x 10⁻⁶ π J (C) 19 x 16⁻⁶ π J (D) 10⁻⁴ π J

Answer 1

Explanation:

r = 1 cm = 10^-2

work done = surface tension*area

= 1.9*10^-2*4π*(10^-2)^2

= 7.6*10^-6 π J

Answer 2

Answer:

(B) 15.2 x 10⁻⁶ π J

Explanation:

In the given Question, we have surface tension of the soap = $1.9×10^{-2}N/m$

and the diameter is = 2.0 cm

surface tension is given in the meter form and diameter is given in the cm form so we convert diameter in meter

so diameter is = $2.0 ×10^{-4}$

so formula for work done to blow a bubble = surface tension × Area

work done to blow a bubble = $1.9×10^{-2}N/m×42.0 ×10^{-4}$ π

work done to blow a bubble =  $15.2×10^{-6} J$π