Transcript Chapter 20 Review 2014

Chapter 20 Review
Which subatomic particle is involved the
transfer of an electrical charge?
ans: electron
Two charged bodies are brought next to each
other resulting in a repelling. This means:
ans: like charged particles
Material that allows for the easy transfer of
an electrical charge is called a(n):
ans conductor
Which statement is more true about a
conductor:
1. conductor have a higher density
2. conductor a have delocalized electrons
ans: both
The type of material that does NOT allow for
the free movement of electrons are:
ans: insulators
Insulators are characterized by:
ans: charges do NOT move
The causal effect of like charge lining up
within a conductor without transferring
from that conductor is called:
ans: induction
“Bleeding off” or expelling excess charges
on a substance is called:
ans grounding
The process of inducing one end of a
substance to be more positive is called:
ans: polarization
Can polarization occur in an insulator?
ans: yes
When charges are induced in a substance
and polarization occurs, what is the net
charge on the substance?
ans: neutral still
What does the term ‘surface charge’ refer to:
ans: polarization of an insulator
Electrostatic equilibrium on a sphere occurs
ans: equally around the sphere
Two charged bodies are moved from 1cm
to 5 cm apart. What effect will this have on
the force between the bodies?
ans: inverse square to distance, 4 cm
increase or 42 = 16 or 1/16 or 16x less F
A cubic conductor has an electrostatic
charge. Where on the cube will the greater
concentration of charge be found?
ans: at the corners, charge accumulate at
areas that cause greater density of charge
With a sphere the accumulation of the charge is on
the surface. What is the charge on the electric
field everywhere:
ans: zero or neutral
Where do the charge accumulate in a conductive
hollow sphere?
ans: on the surface
A sharpened pencil has an accumulation of excess
e-. Will the charges be equally distributed?
NO. Highest density of charge at the
smallest area. At the sharpened tip
Three charged bodies along the x-axis. At
x= 0 cm, q1 = +5 mC, x = 3cm, q2 = -2 mC
and x = 4 cm, q3 = -4 mC. What is the net
force acting on q2? What direction?
ans: 620 N to the left
What is the charge on two equally charged
bodies set 3 cm apart with a force of 63 N
ans: 2.5 x 10-6 C
What is meant by ‘electrostatic equilibrium’?
p+ = e-, any excess charge on surface
An insulator is rubbed on fur or wool, what is
the net charge on the insulator?
(-) due to an excess of electrons
Where is the greatest e- density found on an
irregularly shaped conductor?
the smallest surface area
True or False: Material can be charged by
induction?
An insulator can transfer a charge
through a conductor.
Where would the density of an electrostatic
charge be the greatest for a hollow
conductive sphere?
on the surface
True or False: Polarization can charge both a
conductor and an insulator?
True.
What is the total net charge of an object in
electrostatic equilibrium?
zero
What is the charge on a proton?
+1.6 x 10-19 C
What is the charge on an electron?
-1.6 x 10-19 C
What defines an electric field (E)?
the force that influences a charged body.
E = Felec / q
What is the electric field strength of a charge
that produces a charge of 5 x 10-6 C set at
3 cm.
ans: 4.99 x 107 N/c
An electron enters an electric field of
200 N/C. What force is on the electron.
ans: 3.2 x 10-17 N
Two charged bodies of +10 C and -20C set 5
m apart. What is the electric force and
direction?
ans: -7.2 x 1010 N