Lesson: Energy Stored in Capacitors Physics • 9th Grade

In this lesson, we will learn how to relate the capacitance of and voltage across parallel-plate capacitors to the charge and energy stored in them.

Lesson Plan

Students will be able to

relate the capacitance, , of a capacitor, the potential difference, , across the capacitor, the charge, , stored by the capacitor, and the energy, , stored by the capacitor using the equations , , and ,
determine the work required to change the separation of the plates of a capacitor.

Lesson Worksheet

Q1:

Which of the following formulas correctly relates the energy stored by a parallel plate capacitor to the charge stored by the capacitor and the capacitance of the capacitor?

Q2:

Which of the following formulas correctly relates the energy stored by a parallel plate capacitor to the charge stored by the capacitor and the potential difference across the plates?

Q3:

A very large capacitor has plates with areas of 1.5 m² that are 1.2 mm apart. What would the permittivity of the space between the plates need to be for the capacitor to store 2.5 mC of charge and 150 J of electrical potential energy?