What conditions are required for resonance to occur? a: a wave with the same frequency as an object's natural frequency b: a wave with the same amplitude as the object's natural frequency c: a wave with the same natural wavelength as an object's frequency d: a wave with the same natural frequency as an object's amplitude

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)