Two 1kg masses are heated up on a hot plate for the same amount of time. One is made of copper, the other of iron. The copper one rises from 20° C to 30°C, but the iron one only goes from 20°C to 25°C. Explain why this happens.

Adielectric-filled parallel-plate capacitor has plate area a = 30.0 cm2 , plate separation d = 9.00 mm and dielectric constant k = 3.00. the capacitor is connected to a battery that creates a constant voltage v = 15.0 v . throughout the problem, use ϵ0 = 8.85x10-12 c2/n.m2 . find the energy u1 of the dielectric-filled capacitor.