The surface tension and vapour pressure of water at 30° C are 7.2 × 10-2 N / m and 2.4 × 103, respectively. What is the radius of the smallest droplet of water which can be formed without evaporating at 30° C ?

Question

The surface tension and vapour pressure of water at 30° C are 7.2 × 10-2 N / m and 2.4 × 103, respectively. What is the radius of the smallest droplet of water which can be formed without evaporating at 30° C ? (A)  1.6× 10-2 m  (B)  2.9× 10-3 m  (C)  5.6× 10-4 m  (D)  6.0× 10-5 m

Tardigrade Admin · Accepted Answer

The given, T=7.2 × 10-2 N / m P=2.4 × 103 N / m 2 or Pa R=? We know that, P=(2 T/R) or R=(2 T/P) =(2 × 7.2 × 10-2/2.4 × 103) =6.0 × 10-5 m

Q. The surface tension and vapour pressure of water at $3 0^{\circ} C$ are $7.2 \times 1 0^{- 2} N / m$ and $2.4 \times 1 0^{3}$ , respectively. What is the radius of the smallest droplet of water which can be formed without evaporating at $3 0^{\circ} C$ ?

$1.6 \times 1 0^{- 2} m$

$2.9 \times 1 0^{- 3} m$

$5.6 \times 1 0^{- 4} m$

$6.0 \times 1 0^{- 5} m$

The given, $T = 7.2 \times 1 0^{- 2} N / m$
$P = 2.4 \times 1 0^{3} N / m^{2}$
or Pa $R = ?$
We know that, $P = \frac{2 T}{R}$
or $R = \frac{2 T}{P}$
$= \frac{2 \times 7.2 \times 1 0 ^{- 2}}{2.4 \times 1 0 ^{3}}$
$= 6.0 \times 1 0^{- 5} m$

Q. The surface tension and vapour pressure of water at 30∘C are 7.2×10−2N/m and 2.4×103, respectively. What is the radius of the smallest droplet of water which can be formed without evaporating at 30∘C ?

1.6×10−2m

2.9×10−3m

5.6×10−4m

6.0×10−5m