A stationary electric charge, typically produced by friction, which causes sparks or crackling or the attraction of dust or hair.
Answer:
The change in the charge on the positve plate when the Teflon is inserted is +2.5 nC.
Explanation:
- It can be showed that the capacitance of a parallel-plate capacitor, can be expresssed as follows:
- Where ε, is the dielectric constant of the material that fills the space between plates.
- When this space is filled with air, ε= ε₀ = 8,85*10⁻¹² F/m.
- At the same time, the capacitance of a capacitor, by definition, is as follows:
- If we insert a Teflon slab, in such a way that fills completely the gap between the plates, all other parameters being equal, if ε = 2*ε₀, this means that C₂ = 2* C₁. = 50 pF
- As V₂=V₁ (due to the capacitor remains connected to the same battery) the charge must be the double, so Q₂ = 2* Q₁ = 5 nC.
- So, the change in the charge of the positive plate is +2.5 nC.
Answer:
<em>The flux through the sphere will remain the same, and the magnitude of the electric field will increase by four times.</em>
Explanation:
The electric flux is the number of electric field, passing through a given area. It is proportional to the electric field strength and the area through which this field passes.
If the radius of the sphere is halved, the area of the sphere will reduce by square of the reduction, which will be four times. The electric field lines will become closer together, or technically increase by a fourth of its initial value. The resultant effect is that the electric flux will remain the same.
If originally,
Φ = EA cos∅
where Φ is the electric flux through the sphere
E is the electric field on the sphere
A is the area of the sphere.
If the area of the sphere is reduced to half, then,
the area reduces to A/4,
and the electric field increases to be 4E on the sphere.
The flux now becomes
Φ = 4E x A/4 cos∅
which reduces to
Φ = EA cos∅
which is the initial electric flux on the sphere.
Glass is a very good electrical insulator.
(As long as it's not "leaded" glass.)
