Lab Activity: To Determine the Surface Tension of Water by Capillary Rise Method

Cotyledons are also called-

What is the purpose of adjusting the height of the metallic plate in the apparatus setup?

Consider the radius of the capillary to be $r$ and the height of water inside it to be $h$ in the experiment for finding surface tension by the capillary rise method.  Which one is the correct formula to be used for more precise calculations?

Which one of the following does not cause an error while finding the surface tension by the capillary rise method?

A student is using a microscope with $20$divisions in $1 \mathrm{cm}$ on its main scale and $50$divisions on the vernier scale that are equivalent to $49$divisions of the main scale. He has recorded the main scale reading and the reading for the vernier scale division coinciding with any of the main scale divisions as shown below. 

Which one of the following is the correct height?

The reading for the meniscus of water inside the capillary is taken to find the surface tension of water. Which of the following statements is correct for taking this observation using a travelling microscope?

A student has taken two different sets of observations for the height of water with the capillaries of different radii. The two heights are $2.453 \mathrm{cm}$ and $2.102 \mathrm{cm}$ and the two radii are $0.06 \mathrm{cm}$ and $0.07 \mathrm{cm}$. He forgot to write these observations in the table properly. If $r_1, h_1$ and $r_2, h_2$ are the radii and heights corresponding to two capillaries then which one of the following statements is correct?