問題一覧
1
The net velocity of a charge carrier moving in an electric field
drift velocity
2
The opposition presented to electric current by a material or device
resistance
3
The si unit for resistance is
The ohm
4
The ability of a conductor to store energy in the form of electrically separated charges
capacitance
5
The si unit of capacitance is
farad
6
Formula of electric current
I = /\ Q / /\ t
7
Drift speeds are relatively fast , the magnitude of drift velocities, or drift speeds are typically very fast
false
8
Resistance can be used to control the amount of current in a conductor
true
9
Electrical potential energy in a uniform electric field formula
PE electric = - qEd
10
The ohmic materials with constant resistance can be applied with ohms law
true
11
Is a device that is used to store electrical potential energy. It has many uses , including tuning the frequency of radio receivers
capacitance
12
Resistors can’t be used to control the amount of current in a conductor
false
13
Capacitance for a parallel plate capacitor in a vacuum
c= E0 A/d
14
Formula of capacitance
c=q/ /\ V
15
Electric potential energy is a component of mechanical energy
true
16
Resistance depends on lengths , area , materials and temperature
true
17
The work that must be performed aqainst electric forces to move a charge between the two point in question, divided by the charge
potential difference
18
Electric potential energy stored in a charged capacitor
PE electric = 1/2 Q /\ V
19
Potentiometer doesn’t have variable resistance
false
20
Potential energy associated with a charge due to its position in an electric field
electric potential energy
21
The rate at which electric charges pass through a given area
electric current
22
Formula of resistance
R= /\ V / I
23
Formula of potential difference
/\ V = /\ PE electric / q
24
Capacitance is the ratio of charge to potential difference
true
25
Salt water and perspiration lower the body’s resistance
true
26
Potential difference between a point at infinity and a point near a point charge
/\ V = kc q/ r
27
The work that must be performed aqainst electric forces to move a charge from a reference point to the point in question divided by the charge
electric potential
28
The effect of a dielectric is to reduce the strength of the electric field in a capacitor a capacitor with a dielectric
true
29
Potential difference in a uniform electric field
/\ V= - Ed
30
Electric potential energy can be associated with a charge in a uniform feild
true