Q9. A small spherical droplet of density d is floating exactly half immersed in a liquid of density ρ and surface tension T. The radius of the droplet is (take note that the surface tension applies an upward force on the droplet): r = (1) r = √ 3(d+ρ)g2T (2) √ (d−ρ)gT (3) T (4) 3T r = r = √ (d+ρ)g √ (2d−ρ)g
What This Question Tests
This question involves balancing the weight of a floating droplet with the combined upward forces due to buoyancy and surface tension.
Concepts Tested
Formulas Used
F_buoyancy = V_submerged * ρ_liquid * g
Weight = V_total * d_droplet * g
F_surface tension = T * (circumference)
📚 NCERT Sections This Tests
9.5 — A Small Bulb Is Placed At The Bottom Of A Tank Containing Water To A
Physics Class 12 · Chapter 9
9.5 A small bulb is placed at the bottom of a tank containing water to a depth of 80cm. What is the area of the surface of water through which light from the bulb can emerge out? Refractive index of water is 1.33. (Consider the bulb to be a point source.)
9.3 — A Tank Is Filled With Water To A Height Of 12.5 Cm. The Apparent
Physics Class 12 · Chapter 9
9.3 A tank is filled with water to a height of 12.5 cm. The apparent depth of a needle lying at the bottom of the tank is measured by a microscope to be 9.4 cm. What is the refractive index of water? If water is replaced by a liquid of refractive index 1.63 up to the same height, by what distance would the microscope have to be moved to focus on the needle again?
9.16 — The Pin Appears Raised By 5.0 Cm. It Can Be Seen With An Explicit Ray
Physics Class 12 · Chapter 9
9.16 The pin appears raised by 5.0 cm. It can be seen with an explicit ray diagram that the answer is independent of the location of the slab (for small angles of incidence).
📋 Question Details
- Chapter
- Properties of Matter
- Topic
- Surface tension and buoyancy
- Year
- 2020
- Shift
- 09 Jan Shift 2
- Q Number
- Q9
- Type
- MCQ
- NCERT Ref
- Class 11 Physics Ch 10: Mechanical Properties of Fluids
More from this Chapter
Q24.A cylinder of height 20 m is completely filled with water. The velocity of efflux of water (in ms−1 ) through a small hole on the side wall of the cylinder near its bottom is (1) 10 (2) 20 (3) 25.5 (4) 5
Q26.A wire suspended vertically from one of its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire is (1) 0.2 J (2) 10 J (3) 20 J (4) 0.1 J
Q17.A wire fixed at the upper end stretches by length by applying a force F. The work done in stretching is (1) F/2 (2) Fℓ (3) 2 Fℓ (4) Fℓ/2
Q24.Spherical balls of radius R are falling in a viscous fluid of viscosity η with a velocity v. The retarding viscous force acting on the spherical ball is JEE Main 2004 JEE Main Previous Year Paper (1) directly proportional to R but inversely (2) directly proportional to both radius R and proportional to v. velocity v. (3) inversely proportional to both radius R and (4) inversely proportional to R but directly velocity v. proportional to velocity v.