In Biot number, the characteristic length used is the ratio of the
__________ of the solid.
(A) Volume to surface area
(B) Perimeter to surface area
(C) Surface area to volume
(D) Surface area to perimeter
__________ of the solid.
(A) Volume to surface area
(B) Perimeter to surface area
(C) Surface area to volume
(D) Surface area to perimeter