Fill in the blanks (a) The volume of a cube of side 1 cm is equal to.....m3 (b) The surface area of a solid cylinder of radius 2.0 cm and height 10.0 cm is equal to ... (mm)2 (c) A vehicle moving with a speed of 18 km h-1covers....m in 1 s (d) The relative density of lead is 11.3. Its density is ... .g cm-3or . ...kg m-3.

Question 2.1:
Fill in the blanks
(a) The volume of a cube of side 1 cm is equal to.....m3
(b) The surface area of a solid cylinder of radius 2.0 cm and height 10.0 cm is equal to ... (mm)2
(c) A vehicle moving with a speed of 18 km h-1covers....m in 1 s
(d) The relative density of lead is 11.3. Its density is ... .g cm-3or . ...kg m-3.
Answer:
(a) 1 cm =1/100 m
Volume of the cube = 1 cm3
But, 1 cm3 = 1 cm × 1 cm × 1 cm =
∴1 cm3 = 10-6 m3
Hence, the volume of a cube of side 1 cm is equal to 10-6 m3.
(b) The total surface area of a cylinder of radius r and height h is S = 2πr (r + h).
Given that,
r = 2 cm = 2 × 1 cm = 2 × 10 mm = 20 mm
h = 10 cm = 10 × 10 mm = 100 mm
S = 2  × 3.14 × 20 ×(20 + 100)== 15072 = 1.5 × 104 mm2
(c) Using the conversion,



Therefore, distance can be obtained using the relation: Distance = Speed × Time = 5 × 1 = 5 m
Hence, the vehicle covers 5 m in 1 s.
(d) Relative density of a substance is given by the relation,
Relative density =

Density of water = 1 g/cm3
Again, 1g =
1 cm3 = 10-6 m3
1 g/cm3 =
 
∴ 11.3 g/cm3 = 11.3 × 103 kg/m3