The surface tension of a soap bubble is 0.03 N/m. The work done in increasing the diameter of bubble from 2 cm to 6 cm is . The value of is

Question

The surface tension of a soap bubble is 0.03 N/m. The work done in increasing the diameter of bubble from 2 cm to 6 cm is $α π \times 10^{- 4} J$ . The value of $α$ is ______. (Take $π = 3.14$ ) [2026]

Smart Achievers · Accepted Answer

(3)

$W = Δ U = 2 T [4 π R_{2}^{2} - 4 π R_{1}^{2}]$

$W = 2 \times 3 \times 10^{- 2} \times 4 π [9 \times 10^{- 4} - 1 \times 10^{- 4}]$

$W = 1.92 π \times 10^{- 4} J$

$\Rightarrow α = 1.92$

Solution

Q.
The surface tension of a soap bubble is 0.03 N/m. The work done in increasing the diameter of bubble from 2 cm to 6 cm is $α π \times 10^{- 4} J$ . The value of $α$ is ______. (Take $π = 3.14$ ) [2026]

1 0.86

2 0.64

3 1.92

4 7.68

Ans.
(3)

$W = Δ U = 2 T [4 π R_{2}^{2} - 4 π R_{1}^{2}]$

$W = 2 \times 3 \times 10^{- 2} \times 4 π [9 \times 10^{- 4} - 1 \times 10^{- 4}]$

$W = 1.92 π \times 10^{- 4} J$

$\Rightarrow α = 1.92$

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