A capillary tube of radius 0.1 mm is partly dipped in water (surface tension 70 dyn / cm and glass water contact angle ≃ 0 ∘ ) with 3 0 ∘ inclined with vertical. The length of water risen in the capillary is ________ cm. ( Take g = 9.8 m / s 2 )

h = ρ gr 2 T cos θ = 1 × 980 × 1 0 − 2 2 × 70 × 1 h = 7 100 cm sin 6 0 ∘ = ℓ h ℓ = 3 h × 2 ℓ = 7 100 × 3 2 = 7 × 3 200 = 16.49 cm

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PhysicsFluidSurface TensionMedium2 minPYQ_2025

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A capillary tube of radius 0.1 mm is partly dipped in water (surface tension $70 dyn / cm$ and glass water contact angle $≃ 0^{\circ}$ ) with $3 0^{\circ}$ inclined with vertical. The length of water risen in the capillary is ________ cm.
$($ Take $g = 9.8 m / s^{2})$

Options:

Answer:

Solution:

$h = \frac{2 T cos θ}{ρ gr} = \frac{2 \times 70 \times 1}{1 \times 980 \times 1 0 ^{- 2}} h = \frac{100}{7} cm sin 6 0^{\circ} = \frac{h}{ℓ} ℓ = \frac{h \times 2}{3} ℓ = \frac{100}{7} \times \frac{2}{3} = \frac{200}{7 \times 3} = 16.49 cm$

Stream:JEESubject:PhysicsTopic:FluidSubtopic:Surface Tension

⏱ 2mℹ️ Source: PYQ_2025

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