A hanging tungsten wire with diameter 0.06 cm is initially 2.4 m long. When a 52 kg mass is hung from it, the wire stretches an amount 1.2 cm. A mole of tungsten has a mass of 184 grams, and its density is 19.3 g/cm^3. What is the length of an interatomic bond in tungsten (diameter of one atom)? Find the approximate value of the effective spring stiffness of one interatomic bond in tungsten.