Quantum Theory
Practice Test
1.
Electric power is given by:
a.
P
=
VR
b.
P
=
I
2
R
c.
P
=
IR
d.
P
=
V
2
R
Hint
2.
The direction of the electric field is the direction of the__________.
a.
force on the positive test charge
b.
force on the negative test charge
c.
work done moving the test charge
d.
potential difference
Hint
3.
If the ammeter in Figure 22-3 were moved to the left of the light bulb, what would it read?
a.
2 A
b.
1 A
c.
0 A
d.
4 A
Hint
4.
Both a 1.2-
μ
F and a 5.5-
μ
F capacitor are connected across an 11-V electric potential difference. Which capacitor has the greater charge and what is it?
a.
1.2
μ
F; 1.3×10
-5
C
b.
5.5
μ
F; 6.1×10
-5
C
c.
1.2
μ
F; 6.1×10
-5
C
d.
5.5
&mu
F; 1.3×10
-5
C
Hint
5.
What is a superconductor?
a.
a material with zero resistance
b.
a powerful battery
c.
a magnet
d.
a meterial with a very high resistance
Hint
6.
In Figure 25-13a, if the primary coil's voltage were increased while the current were kept the same, what effect would this have on the secondary coil?
a.
Its power would decrease.
b.
Its number of turns would increase.
c.
Its voltage would increase.
d.
Its current would decrease.
Hint
7.
The oscillations of a coil and capacitor circuit can be compared to a _________.
a.
parabolic path of a ball
b.
ship in orbit
c.
pendulum
d.
merry-go-round
Hint
8.
Einstein predicted that photons had two properties of particles: __________ and __________.
a.
energy; momentum
b.
mass; momentum
c.
energy; mass
d.
momentum; diffraction
Hint
9.
In Figure 24-16, if the magnetic poles were reversed AND the current in the wire were reversed, what would the direction of the magnetic force be?
a.
left
b.
right
c.
down
d.
up
Hint
10.
A Thompson tube is configured like the one in Figure 26-1, such that the electrons sent through the tube hit the center of the screen. If the magnetic field were increased, where would they now hit the screen (from the electron's point of view)?
a.
to the left of center
b.
to the right of center
c.
below the center
d.
above the center
Hint
11.
The electric field at the location of
q'
is represented by which of the following equations?
a.
E
=
q
'
/
F
q
'
b.
E
=
W
/
q
'
c.
E
=
q
/Δ
V
d.
E
=
F
/
q'
Hint
12.
The __________ is a vector quantity that relates the force on a test charge to the size of the charge.
a.
capacitor
b.
electric field
c.
equipotential
d.
potential
Hint
13.
A proton moves at a speed of 4.9×10
4
m/s as it passes through and is perpendicular to a 0.50-T uniform magnetic field. Find the radius of the circular path.
a.
8.2×10
-3
m
b.
5.0×10
1
m
c.
1.0×10
-3
m
d.
5.6×10
-7
m
Hint
14.
The radio waves reflected by a parabolic dish are 4.0 cm long. How long should the antenna be that detects the waves?
a.
2.5 cm
b.
2.0 m
c.
2.0 cm
d.
1.0 cm
Hint
15.
According to Einstein, the energy of a photon depends on the __________ of the electromagnetic radiation.
a.
speed
b.
intensity
c.
momentum
d.
frequency
Hint
16.
In Figure 25-13a, if the primary coil were increased to 10 turns while its voltage and current were kept the same, what effect would this have on the secondary coil?
a.
Its power would increase.
b.
Its voltage would decrease.
c.
Its current would decrease.
d.
Its number of turns would increase.
Hint
17.
An electron is accelerated by a potential difference of 150 V, giving it a velocity of 7.3×10
6
m/s. What is the de Broglie wavelength of this electron?
a.
9.5×10
-11
m
b.
9.5×10
11
m
c.
5.9×10
-24
m
d.
4.9×10
-11
m
Hint
18.
If the combined resistance of the potentiometer and motor in Figure 22-5 is 250 Ω, what is the current through the circuit?
a.
120 A
b.
3000 A
c.
21 A
d.
48 mA
Hint
19.
A beam of protons travels at 3.5 × 10E6 m/s through a uniform magnetic field of 5.7×10
-2
T. The beam of electrons is perpendicular to the field. How strong is the force acting on each proton?
a.
1.6×10
-12
N
b.
3.2×10
-12
N
c.
3.2×10
-14
N
d.
-6.4×10
-14
N
Hint
20.
The Heisenberg uncertainty principle states that it is impossible to precisely measure the __________ of a particle at the same time.
a.
frequency and energy
b.
position and energy
c.
position and momentum
d.
momentum and frequency
Hint
