Solving a problem in physics section 70 point 70 electr

70. A potential difference of U1 = 0.7 kV is applied to the plates of a flat air condenser with a distance between the plates of d = 3 mm and an area of S = 100 cm2. After disconnecting the capacitor from the voltage source, glass was introduced into the space between the plates (ε = 7). Determine: 1) the potential difference U2 between the plates after making the dielectric; 2) the electric capacitance of capacitors C1 and C2 before and after making the dielectric.