The surface tension of water is 0.072 N m- 1 . The excess pressure inside a water drop, of diameter 1.2 mm , is

Question

The surface tension of water is 0.072 N m- 1 . The excess pressure inside a water drop, of diameter 1.2 mm , is (A) 240Nm- 2 (B) 120Nm- 2 (C) 0.06Nm- 2 (D) 72Nm- 2

Tardigrade Admin · Accepted Answer

textitP=(2 textitS/ textitr)=(4 textitS/ textitD)=(4 × 0 text. 0 7 2/1 text. 2 × 1 0- 3)=240 textN textm- 2

Q. The surface tension of water is $0.072 N m^{- 1}$ . The excess pressure inside a water drop, of diameter $1.2 mm$ , is

$240 N m^{- 2}$

$120 N m^{- 2}$

$0.06 N m^{- 2}$

$72 N m^{- 2}$

$P = \frac{2 S}{r} = \frac{4 S}{D} = \frac{4 \times 0 . 072}{1 . 2 \times 1 0 ^{- 3}} = 240 N m^{- 2}$

Q. The surface tension of water is 0.072Nm−1 . The excess pressure inside a water drop, of diameter 1.2mm , is

240Nm−2

120Nm−2

0.06Nm−2

72Nm−2