Solving a problem in physics, section 62, point 64 wave

64. Reel (without core) with a length l = 50 cm and a sectional area S1 of 3 cm2 is N = 1000 turns and is connected in parallel with the capacitor. A capacitor consists of two plates S2 = area of 75 cm2 each. The distance d between the plates is 5 mm. Dielectric - air. Determine the period T of the oscillation circuit.