The nucleus of a copper atom contains how many protons?
1
4
18
29
The net charge of a neutral copper atom is
0
+1
-1
+4
Assume the valence electron is removed from a copper atom. The net charge of the atom becomes
The valence electron of a copper atom experiences what kind of attraction toward the nucleus ?
None
Weak
Strong
Impossible to say
How many valence electrons does a silicon atom have?
2
Which is the most widely used semiconductor?
Copper
Germanium
Silicon
None of the above
How many protons does the nucleus of a silicon atom contain?
14
32
Silicon atoms combine into an orderly pattern called a
Covalent bond
Crystal
Semiconductor
Valence orbit
An intrinsic semiconductor has some holes in it at room temperature. What causes these holes?
Doping
Free electrons
Thermal energy
Valence electrons
When an electron is moved to a higher orbit level, its energy level with respect to the nucleus
Increases
Decreases
Remains the same
Depends on the type of atom
The merging of a free electron and a hole is called
Covalent bonding
Lifetime
Recombination
At room temperature, an intrinsic silicon crystal acts approximately like
A battery
A conductor
An insulator
A piece of copper wire
The amount of time between the creation of a hole and its disappearance is called
Valence
The valence electron of a conductor can also be called a
Bound electron
Free electron
Nucleus
Proton
A conductor has how many types of flow?
3
A semiconductor has how many types of flow?
When a voltage is applied to a semiconductor, holes will flow
Away from the negative potential
Toward the positive potential
In the external circuit
For semiconductor material, its valence orbit is saturated when it contains
One electron
Equal (+) and (-) ions
Four electrons
Eight electrons
In an intrinsic semiconductor, the number of holes
Equals the number of free electrons
Is greater than the number of free electrons
Is less than the number of free electrons
Absolute zero temperature equals
-273 °C
0 °C
25 °C
50 °C
At absolute zero temperature, an intrinsic semiconductor has
A few free electrons
Many holes
Many free electrons
No holes or free electrons
At room temperature, an intrinsic semiconductor has
A few free electrons and holes
No holes
The number of free electrons and holes in an intrinsic semiconductor decreases when the temperature
Stays the same
The flow of valence electrons to the right means that holes are flowing to the
Left
Right
Either way
Holes act like
Atoms
Crystals
Negative charges
Positive charges
Trivalent atoms have how many valence electrons?
5
An acceptor atom has how many valence electrons?
If you wanted to produce a p-type semiconductor, which of these would you use?
Acceptor atoms
Donor atoms
Pentavalent impurity
Electrons are the minority carriers in which type of semiconductor?
Extrinsic
Intrinsic
n-type
p-type
How many free electrons does a p-type semiconductor contain?
Many
Only those produced by thermal energy
Same number as holes
Silver is the best conductor. How many valence electrons do you think it has?
Suppose an intrinsic semiconductor has 1 billion free electrons at room temperature. If the temperature drops to 0°C, how many holes are there?
Fewer than 1 billion
1 billion
More than 1 billion
An external voltage source is applied to a p-type semiconductor. If the left end of the crystal is positive, which way do the majority carriers flow?
Neither
Which of the following doesn't fit in the group?
Conductor
Four valence electrons
Crystal structure
Which of the following is approximately equal to room temperature?
0°C
25°C
50°C
75°C
How many electrons are there in the valence orbit of a silicon atom within a crystal?
8
Negative ions are atoms that have
Gained a proton
Lost a proton
Gained an electron
Lost an electron
Which of the following describes an n-type semiconductor?
Neutral
Positively charged
Negatively charged
Has many holes
A p-type semiconductor contains holes an
Positive ions
Negative ions
Pentavalent atoms
Which of the following describes a p-type semiconductor?
Has many free elctrons
When compared to a germanium diode, a silicon diode's reverse saturation current is
Equal at high temperatures
Lower
Equal at lower temperatures
Higher
What causes the depletion layer?
Barrier potential
Ions
What is the barrier potential of a silicon diode at room temperature?
0.3 V
0.7 V
1 V
2 mV per degree Celsius
When comparing the energy gap of germanium and silicon atoms, a silicon atom's energy gap is
About the same
Unpredictable
In a silicon diode, the reverse current is usually
Very small
Very large
Zero
In the breakdown region
While maintaining a constant temperature, a silicon diode has its reverse-bias voltage increased. The diode's saturation current will
Increase
Decrease
Remain the same
Equal its surface-leakage current
The voltage where avalanche occurs is called the
Depletion layer
Knee voltage
Breakdown voltage
The width of a diode's depletion layer will decrease when the diode is
Forward biased
First formed
Reverse biased
Not conducting
When the reverse voltage decreases from 10 to 5 V, the depletion layer
Becomes smaller
Becomes larger
Is unaffected
Breaks down
When a diode is forward biased, the recombination of free electrons and holes may produce
Heat
Light
Radiation
All of the above
A reverse voltage of 10 V is across a diode. What is the voltage across the depletion layer?
0 V
10 V
The energy gap in a silicon atom is the distance between the valence band and the
Conduction band
Atom's core
The reverse saturation current doubles when the junction temperature increases
1°C
2°C
4°C
10°C
The surface-leakage current doubles when the reverse voltage increases
7%
100%
200%
2 mV