(i)Given radius of the cylinder, r = 3.5 cm

Diameter of the sphere = height of the cylinder

= 3.5×2

= 7 cm

So radius of sphere, r = 7/2 = 3.5 cm

Height of cylinder, h = 7 cm

Total surface area of can in contact with water = curved surface area of cylinder+base area of cylinder.

= 2rh+r²

= r(2h+r)

= 22/7)×3.5×(2×7+3.5)

= (22/7)×3.5×(14+3.5)

= 11×17.5

= 192.5 cm²

Hence the surface area of can in contact with water is 192.5 cm².

(ii)Let the depth of the water before the sphere was put be d.

Volume of cylindrical can = volume of sphere+ volume of water

r²h = (4/3)r³+r²d

r²h = r²{(4/3)r +d)}

h = (4/3)r +d

d = h – (4/3)r

d = 7 – (4/3)×3.5

d = (21-14)/3

d = 7/3

Hence the depth of the water before the sphere was put into the can is 7/3 cm.