Suppose in case we don't have emersion oil to reduce the refraction of light, now we know that, the refractive index of water is about 1.33 which is o

Anup Padwal Best Answer

Yes. You can use water instead of immersion oil but for that purpose you have to use water immersion objective. if you have one you can use water. for regular objective lense you can use the water as immersion with working distance of 3mm. for more information about Water immersion Objective read following information; A less common immersion objective found on research-grade microscopes (and usually confocal microscopes) is the ‘water-immersion’ objective. The water immersion objective is highly recommended when imaging live cells which are in cell medium. There are two types of water immersions objectives ‘water immersion’ and ‘water dipping’. The water dipping objectives are commonly used with an upright microscope configuration and are used to dip directly into water or water-based medium/buffer. The dipping objectives are manufactured to provide a very long working distance. They are also manufactured with steeply angled nose-pieces which are constructed from inert material such as ceramic. Water immersion objectives are used in a manner similar to oil immersion objectives, but with water in place of the drop of oil. One of the advantages of using a water immersion objective is simply that water is used as the immersion medium. This is easy to apply and clean off. Additionally, you do not need to use specific immersion oil depending on the imaging you are carrying out, nor do you need to use an immersion medium as specified by the manufacturer of the microscope and objective. There are, however, some disadvantages when using a water immersion objective. But higher resolution is achievable with oil immersion objectives compared to the aqueous objectives. In addition, due to the viscosity of water the use of water immersion objectives can be susceptible to vibrations and small air movements. Such artefacts can be overcome by ensuring the microscope is placed on an anti-vibration table. Alternatively, a more simple solution is to place a special ring which sits over the slide to create a small pool of water. The final disadvantage of water immersion objectives is their cost. Some water immersion objectives can cost as much as a complete research grade microscope.