Physics 2nd Semester Key Concepts:
Heat Processes:
Adiabatic:
A process in which essentially no heat is lost or gained is referred to as…
Isothermal:
A process which is done in which the temperature does not change appreciably.
Beats:
If one tuning fork vibrates at 440 Hz and another at 443, the # of beats heard is
the difference in their frequencies (443 – 440 = 3 beats).
When comparing the loudness of two sounds in dB (decibels), for example 60dB and 40 dB: first take
the difference (60 dB – 40 dB = 20 dB). Then change to Bels (10 dB in 1 Bel 
2Bels.  The 2nd sound is 102 or 100X louder.
When comparing the loudness of two sounds in dB (decibels) as recognized by your brain through
your ears, for example 60dB and 40 dB: after taking the difference (60 dB – 40
dB = 20 dB) as above, and changing to Bels (10 dB in 1 Bel  2Bels.  The
2nd sound is heard by the ear not as 102 or 100X louder but as 22 or 4X louder.
Identifying pictures of types of waves:
Standing wave:
Longitudinal wave:
Transverse wave:
Electromagnetic wave:
Albert Einstein Significant Dates:
Special Relativity:
1905
General Relativity:
1915/1916
Sir Arthur Eddington verify Einstein’s General Relativity theory during an eclipse of the sun: 1919
Nobel Prize received: 1921
Temperatures of a lake or pond frozen over: Bottom of pond is always 4oC since water is
most dense there
Top of ice
Bottom of ice
Middle of pond
.
Bottom of pond
Fluid principles to memorize:
Archimedes’ Principle: “The buoyant force is equal to the weight of the fluid (H2O) displaced.”
Bernoulli’s principle:
“As the speed of a fluid increases, the pressure decreases.”
Adaptor circuit for charging:
In the schematic below which is that of an adaptor for a laptop, describe the
three steps of converting 120VAC to 6VDC, listing the name of the component(s)
for each step.
What is the component for step 1 above? transformer
What is the component for step 2 above? diode bridge
What is the component for step 3 above? RC smoothing circuitry
In the schematic below which is that of a power adaptor for charging the
battery in a laptop, indicate what each portion does.
In step 1 above, what does that portion of the circuitry do? Lowers the voltage.
In step 2 above, what does that portion of the circuitry do? Converts AC to DC.
In step 3 above, what does that portion of the circuitry do? Smoothes out the ripples
of the DC current.
Infrasonic: A sound which has a frequency lower than the frequencies which the average person
can hear (e.g. 10Hz).
Ultrasonic: A sound which has a frequency higher than the frequencies which the average person
can hear (e.g. 25,000 Hz).
Subsonic:
Traveling at less than the speed of sound (340 m/s). Say 250 m/s
Supersonic: Traveling faster than the speed of sound (340 m/s).
Say 680 m/s (Mach 2).
A boat in a harbor sounds a horn. If the speed of sound in air is 340 m/sec, and the frequency of the
sound made is 384 Hz, then what is the wavelength of the sound wave (in air)? (v = f)
A scuba diver hears the same horn sound under water. If the speed of sound in salt water is 1500
m/sec, then what is the frequency, wavelength and period of the same sound in water?
(HINT: What property doesn’t change?)
Show your work and watch sig figs
________ frequency (f)
What determines the frequency of a wave?
(The source or the medium?)
________ wavelength ()
________ period (T)
Know how to balance nuclear reactions and to recognize: alpha decay, beta decay, neutron capture
(fission) and fusion.
235
92
U +
228
88
Ra 
_
_
209
84
Po 
205
82
234
90
14
7
1
0
Th 
N+
4
2
n
_
_
Ra 
235
92
U 

Pb
+
? +
0
-1
222
86
230
90
Ba +
0
-1
? +
 
226
88
141
56
_
_
Kr + __ 01n
(Natural transmutation by ___ decay)
_
_
?
(Natural transmutation by ___ decay)

? +
Rn +
Th +
92
36
4
2
_
_
1
1
H
0
? + 0 ? (Natural transmutation by ___ decay
with ____ decay.)
 + __ 01n