JAMB - Physics (1983 - No. 25)
1,000 identical drops of oil of density 500kgm-3 have a total mass of 5 x 10-4kg. One of the drops forms a thin film of area 0.5m2 on water. The thickness of the film is
2 x 10-8m
2 x 10-9m
2 x 10-7m
3 x 10-9m
2.8 x 10-8m
Объяснение
Mass of one oil = \(\frac{5 \times 10^{-4}}{1000}\)
= 5 x 10\(^{-7}\)kg
Density = \(\frac{\text {mass}}{\text{area x thickness}}\)
500 = \(\frac{5 \times 10^{-7}}{\text{0.5 x thickness}}\)
thickness = 2 x 10\(^{-9}\)m
= 5 x 10\(^{-7}\)kg
Density = \(\frac{\text {mass}}{\text{area x thickness}}\)
500 = \(\frac{5 \times 10^{-7}}{\text{0.5 x thickness}}\)
thickness = 2 x 10\(^{-9}\)m