While measuring the surface tension of water, by capillary rise method, which of the following precaution is/are necessary.
(i) Capillary tube and water must be clean and free from contamination/grease
(ii) Capillary tube should be set vertical and the temperature of the water should be noted
(iii) Travelling microscope should be moved in lower direction only avoid back lash error
(iv) Internal diameter of capillary tube should be measured in two mutually perpendicular directions