All Flashcards
Compare the electric field with and without a dielectric.
Without a dielectric, the electric field is stronger. With a dielectric, the induced electric field reduces the overall electric field strength.
Compare the capacitance with and without a dielectric.
Without a dielectric, the capacitance is lower (). With a dielectric, the capacitance is higher ().
Compare the dielectric constant of air and water.
Air has a dielectric constant close to 1 (1.00059). Water has a much higher dielectric constant of 80.
Compare the effect on capacitance of materials with high k vs low k
Materials with high k increase capacitance more than those with low k.
Compare a conductor and a dielectric.
A conductor allows free flow of electrons. A dielectric is an insulator that can be polarized.
What is the effect of inserting a dielectric into a capacitor?
It increases the capacitance by allowing more charge to be stored at the same voltage and reduces the electric field strength.
What is the effect of polarization of dielectric molecules?
Creates a layer of opposite charge on the surface, attracting more charge onto the capacitor plates, increasing capacitance.
What happens to the electric field when a dielectric is inserted?
The overall electric field between the plates is weakened due to the induced electric field within the dielectric.
What happens to the voltage when a dielectric is inserted at constant charge?
The voltage is reduced because V = Ed, and the electric field (E) is reduced.
What happens to capacitance when voltage decreases at constant charge?
Capacitance increases, because C = Q/V.
Define 'dielectric'.
An insulating material that increases capacitance when inserted into a capacitor, allowing more charge to be stored at the same voltage.
What is the dielectric constant (k)?
A value representing how much a material can be polarized; the higher the k, the more it boosts capacitance.
Define 'polarization' in the context of dielectrics.
The alignment of molecules within a dielectric material when placed in an electric field, creating a layer of opposite charge on the surface.
What is ?
Capacitance without the dielectric.
What is the dielectric constant of a vacuum?
1
What is the effect of polarization on the electric field?
The overall electric field between the plates is weaker than if there were a vacuum.