Question

The edge of a cube is measured using a vernier callipers. [9 divisions of the main scale is equal to 10 divisions of vernier scale and 1 main scale division is 1 mm]. The main scale division reading is 10 and 1 division of vernier scale was found to be coinciding with the main scale. The mass of the cube is 2.736 g. Calculate the density in g/${cm}^3$ upto correct significant figures.

• A. 1.33 g/${cm}^3$
• B. 2.66 g/${cm}^3$
• C. 3.33 g/${cm}^3$
• D. 5.66 g/${cm}^3$

Answer 1

The correct option is B 2.66 g/${cm}^3$

Edge of cube is $=$ main scale $+$ vernier scale $\times LC$

$=10.1mm=1.01cm$

Volume is ${1.01}^3=1.03c{m}^3$; $3$ significant figures

$density=mass/volume$

$density=2.736/1.03=2.66g/c{m}^3$ ;on the concept of significant figures density also contains 3 significant figures