Question

The work done in increasing the size of the bubble by 10^-2 m2 (T=25 dyne 1cm)

A) 0.4×10^-4 erg
B) 50× 10^2 erg
C) 25× 10^2 erg
D) 25× 10^-2 erg​

Answer 1

Answer:

Step-by-step explanation:

The work done in increasing the size of the bubble by 10^-2 m2 (T=25 dyne 1cm)

A) 0.4×10^-4 erg

B) 50× 10^2 erg

C) 25× 10^2 erg

D) 25× 10^-2 erg​

Answer 2

Option (b) 50 × 10^2 erg is the work done in increasing the size of the bubble.

Solution: The work done in increasing the size of the bubble is equal to the work done against surface tension.

Here, surface tension is denoted by T and let change in surface area be denoted by A.

T = 25 dyne/cm

A = 10^-2 m^2

= 100 cm^2 ( since 1 m^2 = 10^4 cm^2)

A bubble has 2 surface areas which doubles the work done for increasing the size. Therefore, the formula for work done in increasing the size is given by:

W = 2 × T × A

=> W = 2 × 25 × 100

=> W = 50 × 10^2 erg

Therefore, the work done in increasing the size of the bubble is option (b) 50×10^2 erg.