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