Question
Download Solution PDFWork done in blowing the soap bubble in the air of radius 2R is W. Find the work done in blowing the soap bubble of radius R.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFCONCEPT:
- Surface tension: The property of liquid surfaces to shrink into the minimum surface area possible is known as surface tension.
- Work done to blow a bubble, make a drop is calculated by
W = surface tension × surface area of bubble or drop
CALCULATION:
Work done to blow a bubble = Surface tension × surface area
Since the soap bubble is in the air so there will be two surfaces in contact with the air (inside and outside)
Work done to blow a bubble = Surface tension × 2 × surface area of the bubble
Work done to blow a bubble of radius 2R
W = T × 2 × A
W = T × 2 × (4π(2R)2)
W = 32TπR2 .....................(i)
Work done to blow a bubble of radius R
W' = T × 2 × A = T × 2 × (4πR2)
W' = 8TπR2 ........................(ii)
Eq (ii) / eq (i)
So the correct answer is option 4.
Last updated on Jul 18, 2025
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