A half litre bottle has a mass of 80 g. It contains 500 cm of liquid when full. The bottle is filled with olive oil of
density = 0.90g/cm

Calculate the mass of oil in the bottle.
Calculate the mass of the full bottle

An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 26 mm and 103 mm. the electric potential of the inner conductor with respect to the outer conductor is - 700 v (k = 1/4πε 0 = 8.99 × 109 n · m2/c2) the energy stored in a 1.0-m length of this capacitor is closest to