Question -
Answer -
Actual depth of the needle in water,┬аh1┬а= 12.5 cm
Apparent depth of the needle in water,┬аh2┬а= 9.4 cm
Refractive index of water =┬а╬╝
The value of┬а╬╝can be obtained asfollows:
Hence, the refractiveindex of water is about 1.33.
Wateris replaced by a liquid of refractive index,┬а
The actual depth of the needle remains thesame, but its apparent depth changes. Let┬аy┬аbe the newapparent depth of the needle. Hence, we can write the relation:
Hence, the new apparent depth of the needleis 7.67 cm. It is less than┬аh2. Therefore, to focus theneedle again, the microscope should be moved up.
тИ┤Distanceby which the microscope should be moved up = 9.4 тИТ 7.67
=1.73 cm