The correct option is (C) 2.66 {g / (cm3)}.
Explanation:
9 division of main scale = 10 division of vernier scale
9 M = 10 V
Also 1 MSD = 1 mm
We know Least count = M – V
= M – (9/10) M
= (1 / 10) M
= (1 / 10) × 1 mm
= (1 / 10) mm
Measured reading of edge = MSR + VSR (LC)
= 10 + {1 × (1 / 10)}
= 10 + 0.1
= 10.1 mm
Volume of cube = (side)3
∴ V = (10.1)3 mm3
= (1.01)3 cm3
= 1.030 cm3
∴ As edge length is measured up to 3 significant digits, after rounding off up to 3 significant digits.
V = 1.03 cm3
Density = ρ = {(mass) / (volume)}
Hence ρ = {(2.736) / (1.03)} {g / (cm3)}
= 2.6563 = 2.66 g/cm3
∴ ρ = 2.66 g/cm3 (after rounding off to 3 significant digits)