Electric Field of a Sphere

Mr. Anderson explains the electric field of a sphere, starting with historical measurements by Charles Coulomb. He discusses how adding or removing charge affects the electric field and uses a PhET simulation to demonstrate the relationship between distance and field strength. The video covers the inverse square law, showing how electric field strength decreases with the square of the radius. The derived equation incorporates the permittivity of free space and relates to the surface area of a sphere.

Who was the scientist that first measured the electric field of a sphere using a torsion balance?

• James Clerk Maxwell

• Albert Einstein

• Charles Coulomb

• Isaac Newton

What happens to the electric field lines when a negative charge is added to a sphere?

• They become parallel

• They go towards the center

• They disappear

• They move away from the sphere

In the PhET simulation, what was the electric field strength measured at 2 meters away from the charge?

• 0.6 volts per meter

• 2.2 volts per meter

• 1 volt per meter

• 9 volts per meter

What kind of relationship exists between the radius and the electric field strength according to the simulation?

• Exponential

• Direct

• Inverse square

• Linear

What is the formula for the electric field strength around a sphere?

• E = Q / r

• E = Q / r^2

• E = 1 / 4πr

• E = 1 / 4πε₀ * Q / r^2

What does the term 'permittivity of free space' refer to?

• The gravitational constant

• The charge of an electron

• The speed of light in a vacuum

• The resistance to an electric field

What is Coulomb's constant used for in the context of electric fields?

• To find the mass of an object

• To calculate gravitational force

• To measure the speed of light

• To determine electric field strength