Two wires of the same material have resistances in the ratio ` 16 : 81` and lengths in the ratio ` 1 : 4`. Compare their radii of cross-section.

Two wires of different materials have resistances in the ratio 4 : 3 , lengths in the ratio 2 : 1 but have same radii of cross-section. Compare their resistivities.

Two wires of same material , having cross-sectional areas in the ratio 1 : 2 and lengths in the ratio 1 : 4 are stretched by the same force. The ratio of the stresses in the wires will be ………….. .

Two wires 'A' and 'B' of the same material have radii in the ratio 2:1 and lengths in the ratio 4:1 . The ratio of the normal forces required to produce the same change in the lengths of these two wires is

Two wires A and B of same material have radii in the ratio 2 : 1 and lengths in the ratio 4 : 1. The ratio of the normal forces required to produce the same change in the lengths of these two wires is

Two wires made of same material have their electrical resistances in the ratio 1:4 if their lengths are in the ratio 1:2 , the ratio of their masses is