A block of material of volume 2 X 10(^{-5})m(^3) and density 2.5 x 10(^3) kgm(^{-3}) is suspended from a spring balance with half volume of the block immersed in water. What is the reading of the spring balance? (Density of water =1.0×10(^3) kg m(^{-3}) g = 10 ms(^{-2})).
-
A.
0.10N -
B.
0.25N -
C.
0.30N -
D.
0.40N -
E.
0.50N
Correct Answer: Option D
Explanation
Weight of object = mg
= (rho vg) = 2.5 x 10(^3) x 2 x 10(^{-5}) x 10 = 0.5N;
Upthrust = weight of displaced fluid = (rho_{water} vg)
= (frac{1.0 times 10^3 times 2 times 10^{-5} times 10}{2}) = 0.1N
∴Reading = 0.5 – 0.1 = 0.4N