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MCAT Physic Formulas
Terms in this set (69)
n / V
PV = nRT
Energy of a Photon in terms of frequency
E = hf (h = 6.6 * 10^-34)
Energy of a Photon in terms of wavelength
E = hc / lambda (h = 6.6 *10^-34)
Equation: Speed of Light
C = f(Lambda) can be rearranged to solve for frequency or wavelength
P = IV, P=v^2/R, P=I^2R , P = work/time
MRT = molarity
f = 1/T
speed circular object
Mechanical Advantage of a ramp
MA = hypotenuse / height
The rate at which charge moves?
Work done by electric field
work - energy theorem
qv / 2 (also is kinetic energy)
connected in series
Q = It (current * time)
If an object is traveling in uniform circular motion, and the centripetal force acting on the object is suddenly removed, which of the following best describes the object's subsequent motion?
The object will continue to travel in a straight line at a constant velocity
Kinematic equation for Velocity final VF (1)
Vf^2 = Vi^2 +2ad
Kinematic equation Distance (1)
D = Vit + 1/2 at^2
Kinematic equation Distance (2)
D = (Vi + Vf/2) * t
Kinematic equation VF (2)
Vf = Vi + at
Proceeds in a spontaneous fashion, always have cell potentials that are greater than 0 (non negative)
V = IR
C = q/v (amount of charge per volt)
Potential Energy Spring
PE = (1/2)Kx^2
Capacitors in Parallel
Resistors in Series
Pressure in static fluid
P = Pair + density(g)(h)
Capacitance of a parallel plate capacitor
C = epsilon not A / d
V = frequency * lambda (V is constant always speed of light)
Magnetic Field in a solenoid
B = u not n I
menomic for lens
PRI positive images are real and inverted
NVU negative images are virtual and upright
thin lens equation
1/di + 1/do = 1/f
String fixed at both ends
f = v / 2L
KE = 1/2 mv^2
gravitational potential energy
U = mgh
Elastic Potential energy
U = 1/2 Kx^2
when an element undergoes Beta decay, a nuclear neutron is converted to a nuclear proton as the nucleus emits an electron. What happens to the atomic number and atomic mass of an element that undergoes Beta decay?
The atomic number increases, but the atomic mass stays approximately the same
Second floor and top floor separated by 100m, what is the difference in the air pressure of the two levels? (air density 1.2 kg/m^3)
Pressure = density
In which of the following does sound travel most rapidly?
The speed of sound is greatest by far in a solid because of the strong intermolecular bonds and close proximity of the molecules.
In a nearsighted individual, the image of a distant object is focused:
in front of the retina, requiring diverging lens correction
A nearsighted (myopic) person can focus nearby objects but cannot clearly see objects far away. The nearsighted eye has a focal length that is shorter than it should be, so the rays from a distant object form a sharp image in front of the retina
terminal voltage is the voltage provided to the external components of the circuit. The battery voltage (EMF) will be reduced by the voltage required to overcome the internal resistance, so V= EMF - IR
A glass fiber carriers a light digital signal long distances with a minimum loss of amplitude. What optical property of glass allows this phenomenon?
Light can be carried along a distance within a transparent material by means of total internal reflection
How long will it take a runner, starting from rest and accelerating uniformly at 1.5 m/s^2, to travel 3.0m?
D = 1/2a * t^2
t = (2d/a)^1/2
An object is placed upright on the axis of a thin covex lens at a distance of four focal lengths (4f) from the center of the lens. An inverted image appears at a distance of 4/3f on the other side of the lens. What is the ratio of the height of the image to the height of the object?
The ratio of object to image distance equals the ratio of object to image height. (4f/3)/4f = 1/3. The image is demagnified by a factor of 3
A 15 eV photon collides with and ionizes a hydrogen atom. If the atom was originally in the ground state (ionization potential = 13.6 eV), what is the kinetic energy of the ejected electron?
Conservation of energy requires that the 15.0 eV photon energy 1st provides the ionization energy to unbind the electron, and then allows any excess energy to become the electron's kinetic energy.
KE = 15 eV - 13.6 eV = 1.4 eV
An object with 15 grams mass is immersed in benezene and suffers an apparent loss of mass of 5 grams. what is the approximate specific gravity of the object? (specific gravity of benezene = 0.7)
The buoyant force of an object immersed in a fluid is equal to the weight of the fluid displaced by the object (Archimedes' principle). There were 5g displaced thus ratio of object mass to fluid mass is 15/5 = 3. The specific gravity of the object (mass per unit volume compare to water) is 3 *.7 = 2.1
The fundamental resonant wavelength of a pipe open at both ends that is 1m long an 0.1 m in diameter is:
Pipes and tubes have their resonant wavelengths when standing waves develop. An open pipe has its fundamental, resonant wavelength at twice the length of the pipe. Both ends have a displacement antinodes (maximum ampltitudes) with a node in the middle of the pipe. Thus, the pipe is half a wavelength long. The resonant wavelength is independent of the diameter of the pipe
Suppose that a stream of fluid flows steadily through a horizontal pipe of varying cross - sectional diameter. Neglecting viscosity, where is the fluid pressure greatest?
at the point of maximum diameter
Bernoulli's equation for horizontal fluid flow states that the pressure plus KE density of the fluid is constant. If the fluid velocity falls, the KE density decreases so the pressure increases. The fluid velocity is lowest where the diameter of the pipe is a maximum. Thus, the pressure is greatest where the diameter is a maximum
Suppose a certain far - sighted person can see objects clearly no closer than 300 cm away. What is the minimum distance from a plane mirror such a person must be to see his reflection?
A plane mirror produces an image behind its plane at a distance equal to the object distance in front of the plane. If the sum between the object and the image distances must be at least 300 cm, then the mirror must be at half this distance meaning 150 cm
If ocean waves strike the shore every 3 seconds and the horizontal distance between adjacent crests and troughs is 1.0 m, what is the average speed of the waves?
speed of a wave is given by the product of its frequency times its wavelength: v = (f)(lamda). The wave frequency is 1/3s; the wavelength is 2 * 1 m because a crest and the adjacent trough are a half wavelength apart. The wave speed is therefore 2m/3 = 0.67 m/s
An unknown solid weighs 31.6 N. When submerged in water, its apparent weight is 19.8N. what is the specific gravity of the unknown sample?
The specific gravity of the solid, the ratio of its weight to the weight of an equal volume of water, is then: 31.6/(31.6-19.8) = 2.68
where do electric field lines face?
exit from positive and enter negative charges
The advantage of the Doppler ultrasound technique over the standard ultrasound techniques is that is also allows
measuring the blood flow
Doppler Effect in which a sound wave emitted by, or reflected from a moving object, will change its frequency based on the relative speed of the object.
The explanation for the fact that radioactive isotopes of an element exhibit the same chemical behavior as the stable isotopes of the element is that each has the same:
Same atomic number
solving for frequency given wavelenght
f = c / lambda
the phase difference corresponding to a half of a wave is 180 degrees. Half a wave difference in phase between two waves corresponds to destructive interference
An electron is ejected from the cathode by a photon with an energy slightly greater than the work function of the cathode. How will the final KE of the electron upon reaching the anode compare to its initial PE immediately after it has been ejected?
near equality of photon energy and work function means little KE will be left for the e-
What happens to a charged particle in an electric field?
It will accelerate
What will effect the capacitance of a capacitor?
Capacitance depends on the geometric factors only, and in the case of parallel plates, capacitance is proportional to the plate area and inversely proportional to the separation distance of the plates
Why can the positive ions be considered to be fixed during the electrons' oscillations?
an ion is much more massive than an electron
when a sound source moves away from an observer, the observer has the impression that the sound source is:
Lower in frequency than it actually is
which of the following phase changes is used to determine the heat of fusion for a pure substance?
Melting of a solid
Fusion means melting, a chemist can melt a solid or freeze a liquid to determine the heat of fusion of a pure susbtance
why are there no naturally occurring elements that have more protons in their nucleus than uranium does?
The range of the strong nuclear force is too short to hold them together
At terminal velocity, weight = friction, so the net force = 0 thus the acceleration = 0. So, the speed stays constant.