Question Details

The work done in blowing a soap bubble of 10cm radius is (surface tension of the soap solution is 3/100 N/m)

Options

A

75.36 x 10⁻⁴ J

B

37.68 x 10⁻⁴ J

C

150.72 x 10⁻⁴ J

D

75.36 J

Correct Answer :

75.36 x 10⁻⁴ J

Solution :

The correct option is 75.36 x 10��⁴ J.

To find the work done in blowing a soap bubble, let us analyze the physical parameters involved:
1. A soap bubble has two free surfaces in contact with air (one inside and one outside). Therefore, the increase in surface area is twice the area of a single sphere.
2. The radius of the soap bubble is given as:
r=10 cm=0.1 m
3. The surface tension of the soap solution is:
T=3100 N/m=0.03 N/m

The formula for the work done (W) in blowing a soap bubble is given by:
W=T×ΔA
where ΔA is the total increase in surface area. Since a bubble has two surfaces:
ΔA=2×(4πr2)=8πr2

Substituting the expression for ΔA into the work formula:
W=T×8πr2

Now, we substitute the given values:
W=0.03×8×3.14×(0.1)2
W=0.24×3.14×0.01
W=0.7536×0.01
W=0.007536 J

Expressing this value in scientific notation to match the options:
W=75.36×10-4 J

Thus, the work done in blowing the soap bubble is 75.36 x 10⁻⁴ J.

Unlock Our Free Library

Access expert-curated educational resources and study materials—completely free.

Discover more resources

You may also like

Mock Tests

View All
  • JEE
  • intermediate
  • 3 hours
  • chemistry, mathematics, physics

  • JEE
  • intermediate
  • 3 hours
  • chemical engineering, mathematics, physics