The correct option is C 4 cm
Let the radii of sphere and hemisphere be r2 and r1 respectively.
Volume of one hemisphere
V=23πr31
Volume of sixteen hemispheres is 16V.
Volume of new sphere:
V2=43πr32
According to the question,
16V=V2
16×23πr31=43π r32
r32=8r31
r32=23×23 cm3
[Given that: r1 = 2 cm ]
r2=4 cm
r2=4 cm