Question

1.
A microscope is focussed on the coin at the
bottom of a beaker. Water is poured into it and
the microscope is focussed again on the coin.
Some lycopodium powder in sprinkled on surface
of water and microscope is focussed on to the
powder. If the corresponding readings are 1.17,
2.02 and 4.57 cm respectively, find the R.I of
water.
1) 2/3
2) 4/3
3) 3/2
4) 1/2​

Answer 1

Explanation:

Water should be poured to a height h cm so that apparent shift in position of coin is 1 cm.

As y=(1−

n

1

)h

⇒h=

(1−

n

1

)

y

=

(1−

4/3

1

)

1

=

4

1

1

=4cm