In an experiment to measure surface tension of completely wetting liquid, the capillary was dipped in liquid. The level of water in beaker was measured using travelling microscope to be 1.43 cm. The level of water in capillary was measured to be 6.23 cm. The readings for inner diameter were 0.00 cm and 0.32 cm respectively. Neglect the expansion of capillary and water on heating.
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Question

In an experiment to measure surface tension of completely wetting liquid, the capillary was dipped in liquid. The level of water in beaker was measured using travelling microscope to be 1.43 cm. The level of water in capillary was measured to be 6.23 cm. The readings for inner diameter were 0.00 cm and 0.32 cm respectively. Neglect the expansion of capillary and water on heating.

Select all that apply

G1 Physics · Accepted Answer

Rise h = 6.23−1.43 = 4.80 cm and capillary diameter d = 0.32 cm. Propagating travelling-microscope uncertainties gives about 0.4% error in h. Increasing temperature lowers surface tension, so capillary rise decreases. The measured surface tension is consistent with 0.38±0.04 N m⁻¹. Correct answers: A,C,D.