Answer:
correct option is C) 2.8
Step-by-step explanation:
given data
string vibrates form = 8 loops
in water loop formed = 10 loops
solution
we consider mass of stone = m
string length = l
frequency of tuning = f
volume = v
density of stone =
case (1)
when 8 loop form with 2 adjacent node is
so here
..............1
and we know velocity is express as
velocity = frequency × wavelength .....................2
= f ×
here tension = mg
so
= f ×
..........................3
and
case (2)
when 8 loop form with 2 adjacent node is
..............4
when block is immersed
equilibrium eq will be
Tenion + force of buoyancy = mg
T + v × × g = mg
and
T = v × - v ×
× g
from equation 2
f × = f ×
.......................5
now we divide eq 5 by the eq 3
solve irt we get
so
relative density
relative density = 2.78 ≈ 2.8
so correct option is C) 2.8