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Physics and Math Flashcards

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1
Q

When rounding decimals for multiplication and division , what direction do you round?

A

multiplication: numbers in opposite directions
division: both numbers in the same direction

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2
Q

What are the rules for significant figures?

A

1) Count all numbers between the first nonzero digit on the left and the last nonzero digit on the right
2) Any zeroes to the left of the first nonzero digit are not significant
3) If there are zeroes to the right of the last nonzero digit and there is a decimal point in the number, then those zeroes are significant. If there is no decimal point then they are not significant (3,490: 3, 3,490.0: 5)
4) For measurements, the last digit is an estimation and is not significant

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3
Q

Exponent rule: what is any number to the zeroth power?

A

X^0 = 1

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4
Q

Exponent rule: multiplication (same base number)

A

X^A x X^B = X^(A+B)

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5
Q

Exponent rule: division (same base number)

A

X^A / X^B = X^(A-B)

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6
Q

Exponent rule: raised to two powers

A

(X^A)^B = X^(AxB)

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7
Q

conversion on log to ln

A

logx = lnx/2.303

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8
Q

What is the kinetic energy equation?

A 
K = 1/2mv^2
m = mass in kilograms
v = speed in meters per second
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9
Q

What is the gravitational potential energy equation?

A 
U = mgh
U = potential energy
m = mass in kilograms
g = acceleration due to gravity (9.8 m/s^2)
h = the height of the object
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10
Q

What is the elastic potential energy equation?

A 
U = 1/2kx^2
U = potential energy
k = the spring constant
x = the magnitude of displacement from equilibrium
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11
Q

What is total mechanical energy and its equation?

A

total mechanical energy is the sum of an object’s potential and kinetic energies

E = U + K
U = potential energy
K = kinetic energy
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12
Q

What is the equation for work?

A 
W = F x d = Fdcos(theta)
W = work
F = the magnitude of the applied force
d = the magnitude of the displacement through which the force is applied
theta = the angle between the applied force vector and the displacement vector
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13
Q

How do you calculate work for processes in which pressure remains constant?

A

W = P x deltaV

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14
Q

What is the equation for power?

A 
P = W/t = deltaE/t
P = power
W = work (which is equal to deltaE, the change in energy)
t = the time over which work is done
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15
Q

What is the work-energy theorem equation?

A

Wnet = deltaK = Kf - Ki

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16
Q

What is mechanical advantage and its equation?

A

mechanical advantage is the ratio of magnitudes of the force exerted on an object by a simple machine (Fout) to the force actually applied on the simple machine (Fin)
mechanical advantage = Fout/Fin

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17
Q

What is the equation for efficiency?

A

efficiency = Wout/Win = (load)(load distance)/(effort)(effort distance)

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18
Q

What is the equation for Fahrenheit to Celsius?

A

F = 9/5C + 32

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19
Q

What is the equation for Kelvin to Celsius?

A

K = C + 273

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20
Q

What is the zeroth law of thermodynamics?

A

when two objects are both in thermal equilibrium with a third object, they are in thermal equilibrium with each other. By extension, no heat flows between two objects in thermal equilibrium

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21
Q

How do the initial length of an object and the amount it expands for a given temperature change relate to one another?

A

Expansion is a result of an increase in dimension at all points along an object. If an object is initially longer, it will experience a greater expansion. This is also represented in the formula for thermal expansion because there is a direct relationship between length change and the initial length of the object.

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22
Q

Can a closed system transfer matter? Energy?

A

it cannot transfer matter but it can transfer energy

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23
Q

Can an isolated system transfer matter? Energy?

A

it cannot transfer matter nor energy

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24
Q

Can an open system transfer matter? Energy?

A

it can transfer both matter and energy

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25
Q

What is the difference between a state function and a process function?

A

State functions are variables independent from the path taken to achieve a particular equilibrium and are properties of a given system at equilibrium; they may be dependent on one another. Process functions define the path (or how the system got to its state) through variables such as heat or work.

State functions: pressure (P), density (p), temperature (T), volume (V), enthalpy (H), internal energy (U), Gibbs free energy (G), and entropy (S)
Process functions: heat (Q), and work (W)

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26
Q

Describe the relationship between internal energy, work, and heat

A

The change in internal energy of a system is equal to heat put into a system minus the work done by the system (first law of thermodynamics)

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27
Q

Define the form of heat transfer: conduction

A

heat exchange by direct molecular interactions

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28
Q

Define the form of heat transfer: convection

A

heat exchange by fluid movement

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29
Q

Define the form of heat transfer: radiation

A

heat exchange by electromagnetic waves (does not depend on matter)

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30
Q

How is work calculated in P-V diagrams?

A

work is the area under the curve (or within a closed loop)

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31
Q

Describe entropy on a macroscopic level and in statistical terms

A

On a macroscopic level, entropy can be thought of as the tendency toward disorder. Statistically, entropy is the measure of the spontaneous dispersal of energy at a specific temperature, increasing the number of available micro states for a given molecule.

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32
Q

What is the relationship between the entropy of a system and its surroundings for any thermodynamic process?

A

the entropy of a system and its surrounding will never decrease; it will always either remain zero or increase

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33
Q

How does gauge pressure relate to the pressure exerted by a column of fluid?

A

Gauge pressure is equal to the pressure exerted by a column of fluid plus the ambient pressure above the fluid, minus atmospheric pressure. When atmospheric pressure is the only pressure above the fluid column, then gauge pressure equals the fluid pressure

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34
Q

What is the relationship between weight and density?

A

Weight is density times volume and acceleration due to gravity

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35
Q

What is the SI unit for pressure? What are other common units for pressure?

A

The SI unit for pressure is the pascal. Other common units include mmHg, torr, and atm

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36
Q

True or false: density is a scalar quantity

A

true, density is directionless, and is thus a scalar quantity

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37
Q

Contrast cohesion and adhesion.

A

Cohesion is the attractive force experienced by molecules of a fluid for one another. Adhesion is the attractive force experienced by molecules of a fluid for a different material (usually a solid)

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38
Q

What would the meniscus of a liquid that experiences equal cohesive and adhesive forces look like?

A

If adhesive and cohesive forces are equal, then no meniscus would form and the liquid surface would be flat

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39
Q

A block is fully submerged three inches below the surface of a fluid, but is not experiencing any acceleration. What can be said about the displaced volume of fluid and the buoyant force?

A

The displaced volume is equal to the volume of the block. The buoyant force is equal tot he weight of the block, and is equal to the weight of the displaced fluid. By extension, the block and the fluid in which it is immersed must have the same density

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40
Q

True or false: to determine the volume of an object by fluid displacement it must have a specific gravity greater than 1

A

False. A fluid with a low specific gravity can be used instead of water to determine volumes of objects that would otherwise float in water

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41
Q

To which side of a hydraulic lift would the operator usually apply a force - the side with the larger cross-sectional area, or the side with the smaller cross-sectional area? Why?

A

The operator usually applies a force to the side with the smaller cross-sectional area. Because pressure is the same on both sides of the lift, a smaller force can be applied on the smaller surface area to generate the desired pressure

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42
Q

Define dynamic pressure

A

the pressure associated with flow, and is represented by 1/2pv^2

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43
Q

Define static pressure

A

the pressure associated with position; static pressure is sacrificed for dynamic pressure during flow

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44
Q

Define pitot tube

A

a pitot tube is a device that measures static pressure during flow to calculate speed

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45
Q

Define viscosity

A

a measure of the resistance of a liquid to flow

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46
Q

Define laminar flow

A

flow in which there are no eddies and in which streamlines roughly parallel to each other

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47
Q

Define turbulence

A

the presence of back flow or current eddies

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48
Q

How do the following concepts relate to one another: Venturi effect, Bernoulli’s equation, and continuity equation? What relationship does each describe?

A

The continuity equation describes the relationship of flow and cross-sectional area in a tube, while Bernoulli’s equation describes the relationship between height, pressure, and flow. The Venturi effect is the direct relationship between cross-sectional area and pressure, and results from the combined relationships of the Bernoulli and continuity equations.

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49
Q

What effect would increasing each of the following have on flow rate: the radius of the tube, pressure gradient, viscosity, and length of the tube?

A

Flow rate would increase when increasing either the radius of the tube or the pressure gradient, but would decrease with increasing viscosity or length of the tube

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50
Q

Under what conditions could the continuity equation be applied to human circulation?

A

The continuity equation cannot be applied to human circulation. The presence of pulses, the elasticity of the vessels, and the nature of the pressure gradient preclude this type of analysis. Poiseuille’s law should instead be used for isolated segments

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51
Q

During exhalation, how does the total resistance of the encountered airways change as air leaves the alveoli to escape the nose and mouth?

A

Total resistance increases as the air exits the body despite the increase in the diameter of the airways. This is because there are fewer airways in parallel with each other

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52
Q

How does flow in the venae cavae relate to flow in the main pulmonary artery?

A

In theory, there should be equal flow in the venae cavae and the main pulmonary trunk. In reality, the flow in the venae cavae is actually slightly less than in the pulmonary trunk because some of the blood entering the right side of the heart is actually from cardiac (coronary) circulation, not systemic circulation.

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53
Q

When placed one meter apart from each other, which will experience a greater acceleration: one coulomb of electrons or one coulomb of protons?

A

The electrons will experience the greater acceleration because they are subject to the same force as the protons but have a significantly smaller mass

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54
Q

Categorize the following materials as either conductors or insulators: blood, hair, copper, glass, iron, sulfuric acid, and distilled water

A

Conductors: blood, copper, iron, sulfuric acid

Insulators: hair, glass, distilled water

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55
Q

What is the net charge of an object with one coulomb of electrons and 3 moles of neutrons?

A

The net charge will be -1 C; neutrons do not contribute charge

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56
Q

What is the electric field midway between two negative charges in isolation?

A

The electric field would be 0 because the two charges are the same. In this case, the fields exerted by each charge at the midpoint will cancel out and there will be no electric field

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57
Q

What direction does a negative electrostatic force point? What direction does a positive electrostatic force point?

A

For a pair of charges, a negative electrostatic force points from one charge to the other (attractive), while a positive electrostatic force points from one charge away from the other (repulsive).

58
Q

How do distance and charge relate to electrostatic force and electric field?

A

Electrostatic force is directly related to each charge and related to the distance by an inverse square relationship. Electric field is unrelated to test charge but is still related to distance by an inverse square relationship. Note that it is the source charge that creates the electric field - not the test charger - so we cannot use the equation E = Fe/q to determine a relationship.

59
Q

How does a change is electric potential energy from -4 J to -7 J reflect on the stability of a system?

A

A decrease in potential energy indicates that the system has become more stable. Keep in mind that negative numbers with larger absolute values are more negative, and represent a decrease in value from negative numbers with smaller absolute values (that is, -4 > -7 even though |-4| > |-7|)

60
Q

Compare the relationship between electrical potential energy and Coulomb’s law to the relationship between gravitational potential energy and the universal law of gravitation.

A

Electrical potential energy is Coulomb’s law multiplied by distance, whereas gravitational potential energy is the universal law of gravitation multiplied by distance

61
Q

How does electric potential energy change between two particles as the distance between them increases?

A

If both particles have the same charge, the electrical potential energy decreases as distance increases. If the two particles have opposite charges, then the electrical potential energy increases as distance increases

62
Q

By what factor would electric potential energy change if the magnitude of both charges were doubled and the distance between them was halved?

A

As given by the equation U = kQq/r, the electric potential energy would increase by a factor of eight if both charges are doubled and the radius is halved

63
Q

What is the difference between electric potential and voltage?

A

Electrical potential is the ratio of a charge’s electrical potential energy to the magnitude of the charge itself. Voltage, or potential difference, is a measure of the change in electrical potential between two points, which provides an indication fo the tendency toward movement in one direction or the other

64
Q

How will a charge that is placed at a point of zero electric potential move relative to a source charge?

A

A charge will move in such a way to minimize its potential energy. Placing a charge at a point of zero electrical potential does not indicate that there is zero potential difference, so the charge may or may not move - and if it moves, it may move toward or away from the source charge depending on the sign of the source charge and test charge

65
Q

True or false: The units of electric potential energy and electric potential are different

A

True. Electrical potential energy is measured in joules (J), while electrical potential and potential difference (voltage) are measured in volts (V).

66
Q

Define equipotential lines

A

Equipotential lines are the sets of points within space at which the potential difference between any two points is zero. This is best visualized as concentric spheres surrounding a source charge.

67
Q

Define electric dipole

A

An electric dipole is the separation of charge within a molecule such that there is a permanent or temporary region of equal and opposite charges at a particular distance.

68
Q

What is the voltage between two points on an equipotential line? Will this voltage cause a charge to move along the line?

A

There is no voltage between two points on an equipotential line, so there will be no acceleration along the line. However, there is a potential difference between different sets of equipotential lines, which can cause particles to move and accelerate

69
Q

Why is the electrical potential at points along the perpendicular bisector of a dipole zero?

A

The perpendicular bisector of an electric dipole is an equipotential plane that is perpendicular to the axis of the dipole. As such, the equation V = kqd/r^2 cos(theta) is necessarily equal to 0 because cos(90) = 0

70
Q

What is the behavior of an electric dipole when exposed to an external electric field?

A

A dipole will rotate within an external electric field such that its dipole moment aligns with the field

71
Q

What are the requirements to have a nonzero electric field? A nonzero magnetic field? A nonzero magnetic force?

A

To create an electric field, one needs a charge. To create a magnetic field, one needs a charge that must also be moving. To create a magnetic force, one needs an external electric field acting on a charge moving any direction except parallel or antiparallel to the external field

72
Q

Define current and provide its SI units

A

Current is the movement of positive charge through a conductive material over time and is given in ampéres (C/s)

73
Q

Define voltage and provide its SI units

A

Voltage is a potential difference between two points and is given in volts (J/C)

74
Q

Define electromotive force (emf) and provide its SI units

A

Electromotive force (emf) refers to the potential difference of the voltage source for a circuit, usually a battery, and is given in volts

75
Q

Define conductivity and provide its SI units

A

Conductivity is the reciprocal of resistance and is a measure of permissiveness to current flow; it is measured in siemens (S)

76
Q

Which likely has a higher conductivity: 1 M glucose or 0.25 M NaCl? Why?

A

The sodium chloride solution likely has a higher conductivity because it is a salt and will increase the ion content of water. Glucose does not dissociate, and therefore it has a near-zero impact on conductivity

77
Q

True or false: in a circuit, the number of electrons entering a point and leaving that point are the same

A

True. This is a restatement of Kirchhoff’s junction rule

78
Q

True or false: the sum of the voltage sources in a circuit is equal to the sum of the voltage drops in that circuit

A

False. While the voltage sources and voltage drops are equal in any closed loop, this is not necessarily true for the entire circuit. For example, a 9V battery that powers 10 light bulbs in parallel has a 9V voltage source and a 9V drop across each light bulb - a total of 90V of drops across all of the light bulbs combined.

79
Q

How does adding or removing a resistor change the total resistance of a circuit with resistors in series? In parallel?

A

Adding a resistor in series increases the total resistance of a circuit; removing one in series decreases the total resistance in the circuit. These relationships are reversed in parallel: adding a resistor decreases resistance while removing one increases it.

80
Q

What four physical quantities determine the resistance of a resistor?

A

Resistivity, length, cross-sectional area, and temperature all contribute to the resistance of a resistor

81
Q

How does power relate to current, voltage, and resistance?

A

Power is related to current, voltage, and resistance through the equations:
P = IV = I^2R = V^2/R

82
Q

True or false: the internal resistance of a battery will lower the amount of current it can provide

A

True. The internal resistance will lower the available voltage for the circuit. Lowering the available voltage will also lower current for any given resistance.

83
Q

Assuming the plates are attached by a conducting material, how does a capacitor behave after the voltage source has been removed from a circuit?

A

The capacitor discharges, providing a current in the opposite direction of the initial current

84
Q

How does dielectric material impact capacitance? Voltage? Charge?

A

A dielectric material will always increase capacitance. If the capacitor is isolated, its voltage will decrease when a dielectric material is introduced; if it is in a circuit, its voltage is constant because it is dictated by the voltage source. If a capacitor is isolated, the stored charge will remain constant because there is no additional source of charge; if it is in a circuit, the stored charge will increase.

85
Q

How does adding or removing a capacitor change the total capacitance of a circuit with capacitors in series? in parallel?

A

Adding a capacitor in series decreases the total capacitance of a circuit; removing one in series increases the total capacitance in the circuit. These relationships are inverted in parallel: adding a capacitor increases capacitance while removing one decreases it.

86
Q

What physical qualities contribute to the capacitance of a capacitor?

A

Surface area, distance, and dielectric constant all contribute to the capacitance if a capacitor.

87
Q

What does an ammeter measure? Where is it placed in a circuit? What is its ideal resistance?

A

An ammeter measures current. It is placed in series with a point of interest in a circuit. Its ideal resistance is 0.

88
Q

What does a voltmeter measure? Where is it placed in a circuit? What is its ideal resistance?

A

A voltmeter measures potential difference (voltage). It is placed in parallel with circuit elements of interest. Its ideal resistance is infinity.

89
Q

What does an ohmmeter measure? Where is it placed in a circuit? What is its ideal resistance?

A

An ohmmeter measures resistance. It is placed at two points in series with a circuit element of interest. Its ideal resistance is 0.

90
Q

True or false: a voltmeter and an ammeter should not be placed in the same circuit

A

False. Voltmeters and ammeters are designed to have minimum impact on a circuit; thus, they can be used together.

91
Q

Define wave speed

A

Wave speed is the rate at which a wave transmits the energy or matter it is carrying. Wave speed is the product of frequency and wavelength

92
Q

Define frequency

A

Frequency is a measure of how often a waveform passes a given a point in space. It is measured in Hz

93
Q

Define angular frequency

A

Angular frequency is the same as frequency, but is measured in radians per second

94
Q

Define period

A

Period is the time necessary to complete a wave cycle

95
Q

Define equilibrium position

A

The equilibrium position is the point with zero displacement in an oscillating system

96
Q

Define amplitude

A

Amplitude is the maximal displacement of a wave from the equilibrium position

97
Q

Define traveling wave

A

Traveling waves have nodes and antinodes that move with wave propagation

98
Q

Define standing wave

A

Standing waves have defined nodes and antinodes that do not move with wave propagation

99
Q

If two waves are out of phase at any interval besides 180 degrees, how does the amplitude of the resultant wave compare to the amplitudes of the two interfering waves?

A

If two waves are perfectly in phase, the amplitude of the resulting wave is equal to the sum of the amplitudes of the interfering wave. If two waves are perfectly out of phase, the amplitude of the resulting wave is the difference of the amplitudes of the interfering waves. Therefore, if the two waves are anywhere between these two extremes, the amplitude of the resulting wave will be somewhere between the sum and difference of the amplitudes of the interfering waves

100
Q

True or false: sound waves are a prime example of transverse waves

A

False. Sound waves are the most common example of longitude waves on the MCAT

101
Q

How does applying a force at the natural frequency of a system change the system?

A

The object will resonate because the force frequency equals the natural (resonant) frequency. The amplitude of the oscillation will increase

102
Q

How is sound produced and transmitted?

A

Sound is produced by mechanical vibrations. These are usually generated by solid objects like bells or vocal cords, but occasionally can be generated by fluids. Sound is propagated as longitudinal waves in matter, so it cannot propagate in a vacuum.

103
Q

To which properties of a sound wave do amplitude and frequency correspond?

A

The amplitude of a wave is related to its sound level (volume). The frequency of a wave is related to its pitch

104
Q

If two objects are traveling toward each other, how does the apparent frequency differ from the original frequency? What if two objects are traveling away from each other? What is one object is following the other?

A

When two objects are traveling toward each other, the apparent frequency is higher than the original frequency.

When two objects are traveling away from each other, the apparent frequency is lower than the original frequency.

When one object follows the other, the apparent frequency could be higher, lower, or equal to the original frequency depending on the relative speeds of the detector and the source

105
Q

What phenomena can be detected or treated using ultrasound?

A

Ultrasound can be used for prenatal screening or to diagnose hailstones, breast and thyroid masses, and blood clots. It can be used for needle guidance in a biopsy, for dental cleaning, and for treating deep tissue injury, kidney stones, certain small tumors, and cataracts, among many other applications

106
Q

Order the types of electromagnetic radiation from highest energy to lowest energy. What other property of light follows the same trend?

A

gamma-rays > X-rays > ultraviolet > visible light > infrared > microwave > radio.

Frequency follows the same trend as energy, whereas wavelength follows the opposite trend

107
Q

True or false: light waves are longitudinal because the direction of propagation is perpendicular to the direction of oscillation.

A

False. Light waves are transverse because the direction of propagation is perpendicular to the direction of oscillation

108
Q

What are the boundaries of the visible spectrum? How does the range of the visible spectrum compare to the range of the full electromagnetic spectrum?

A

Visible light ranges from wavelengths of about 400 nm to 700 nm. This is in comparison to the entire EM spectrum which ranges from wavelengths of nearly 0 to 10^9 m.

109
Q

Describe the sign conventions for mirrors

A

o) positive: object is in front of mirror, negative: object is behind mirror (extremely rare)
i) positive: image is in front of mirror (real), negative: image is behind mirror (virtual)
r) positive: mirror is concave (converging), negative: mirror is convex (diverging)
f) positive: mirror is concave (converging), negative: mirror is convex (diverging)
m) positive: image is upright (erect), negative: image is inverted

110
Q

Describe the sign conventions for lenses

A

o) positive: object is on same side of lens as light source, negative: object is on opposite side of lens from light source (extremely rare)
i) positive: image is on opposite side of lens from light source (real), negative: image is on same side of lens as light source (virtual)
r) positive: lens is convex (converging), negative: lens is concave (diverging)
f) positive: lens is convex (converging), negative: lens is concave (diverging)
m) positive: image is upright (erect), negative: image is inverted

111
Q

True or false: incident angle is always measured with respect to the normal

A

Ture. In optics, incident angles are always measured relative to the normal

112
Q

Describe the bending of light when moving from a medium with low refractive index to high refractive index

A

Light will bend toward the normal when going from a medium with low n to high n

113
Q

Describe the bending of light when moving from a medium with high refractive index to low refractive index

A

Light will bend away from the normal when going from a medium with high n to low n; if the incident angle is larger than the critical angle (theta c), total internal reflection will occur

114
Q

Define dispersion

A

Dispersion is the tendency for different wavelengths of light to experience different degrees of refraction in a medium, leading to separation of light into the visible spectrum (a rainbow)

115
Q

Define aberration

A

Aberration (spherical or chromatic) is the alteration or distortion of an image as a result of an imperfection in the optical system

116
Q

What are the two mathematical relationships between image distance and object distance?

A

1/f = 1/o + 1/i

m = -i/o

117
Q

How does the diffraction pattern for a single slit differ from a slit with a thin lens?

A

Diffraction through a single slit does not create characteristic fringes when projected on a screen, although the light does spread out. When a lens is introduced into the system, the additional refraction of light causes constructive and destructive interference, creating fringes.

118
Q

What wave phenomenon do diffraction fringes result from?

A

Fringes result from constructive and destructive interference between light rays

119
Q

How does double-slit diffraction and interference differ from single-slit diffraction?

A

The image formed during double-slit diffraction contains fringes because light rays constructively and destructively interfere. A single slit forms an image of a wide band of light, spread out from its original beam.

120
Q

True or false: maxima in diffraction patterns are always equidistance between two minima.

A

True. Maxima and minima alternate in a diffraction pattern. A maximum is equidistant between two minima, and a minimum is equidistant between two maxima.

121
Q

Contrast plane-polarized and circularly polarized light

A

Plane-polarized light contains light waves with parallel electric field vectors. Circularly polarized light selects for a given amplitude and has a continuously rotating electric field direction

122
Q

How does the application of a polarized filter impact the wavelength of light passing through the filter?

A

Plane polarization has no effect on the wavelength (or frequency or speed) of light. Polarization does affect the amount of light passing through a medium and light intensity.

123
Q

How does the work function relate to the energy necessary to emit an electron from a metal?

A

The work function describes the minimum amount of energy necessary to emit an electron. Any additional energy from a photon will be converted to excess kinetic energy during the photoelectric effect.

124
Q

What does the threshold frequency depend on?

A

The threshold frequency depends on the chemical composition of a material (that is, the identity of the metal).

125
Q

What electrical phenomenon results from the application of the photoelectric effect?

A

The accumulation of moving electrons creates a current during the photoelectric effect.

126
Q

What determines the absorption spectrum of a single atom?

A

The energy differences between ground-state electrons and higher-level electron orbits determine the frequencies of light a particular material absorbs (its absorption spectrum)

127
Q

True or false: small changes in the chemical structure only minimally impact light absorption and emission patterns

A

False. Small changes, such as protonation and deprotonation, change in oxidation state or bond order, and others may cause dramatic changes in light absorption in a material.

128
Q

During which electronic transitions is photon emission most common?

A

When electrons transition from a higher-energy state to a lower-energy state, they will experience photon emission

129
Q

What causes fluorescence?

A

Fluorescence is a special stepwise photon emission in which an excited electron returns to the ground state through one or more intermediate excited states. Each energy transition releases a photon of light. With smaller energy transitions than the initial energy absorbed, these materials can release photons of light in the visible range.

130
Q

Define strong nuclear force

A

The strong nuclear force is one of the four primary forces and provides the adhesive force between the nucleons (protons and neutrons) within the nucleus.

131
Q

Define mass defect and binding energy

A

Mass defect is the apparent loss of mass when nucleons come together, as some of the mass is converted into energy. That energy is called the binding energy

132
Q

What are the four fundamental forces of nature?

A

The four fundamental forces of nature are the strong and weak nuclear forces, electrostatic forces, and gravitation.

133
Q

How does the mass defect relate to the binding energy?

A

Mass defect is related to the binding energy such that there is a transformation of nuclear matter to energy with a resultant loss of matter. They are related by the equation E = mc^2

134
Q

True or false: nuclear fission and nuclear fusion both release energy

A

True. While they seem like inverses of each other, both nuclear fusion and nuclear fission reactions release energy

135
Q

Compare and contrast nuclear fission and nuclear fusion reactions

A

Size of reactant particles: Nuclear fission has large reactant particles (actinides, lanthanides). Nuclear fusion has small reactant particles (hydrogen, helium)

Change in nuclear mass during reaction (increase or decrease): Nuclear fission decrease, nuclear fusion increase

136
Q

What does alpha decay emit, what is its ΔZ and ΔA?

A

Alpha decay emits an alpha particle, its ΔZ is -2 and ΔA is -4

137
Q

What does beta-negative decay emit, what is its ΔZ and ΔA?

A

Beta-negative decay emits and electron and antineutrino, its ΔZ is +1 and ΔA is 0

138
Q

What does beta-positive decay emit, what is its ΔZ and ΔA?

A

Beta-positive decay emits a positron and neutrino, its ΔZ is -1 and ΔA is 0

139
Q

What does gamma decay emit, what is its ΔZ and ΔA?

A

Gamma decay emits a gamma ray, its ΔZ is 0 and ΔA is 0

140
Q

What does electron capture emit, what is its ΔZ and ΔA?

A

Electron capture emits nothing (absorbs an electron from inner shell), its ΔZ is -1 and ΔA is 0

141
Q

How many half-lives are necessary for the complete decay of a radioactive sample?

A

Because the amount remaining is cut in half after each half-life, the portion remaining will never quite reach zero. This is mostly a theoretical consideration; “all” of a sample is considered to have decayed 7 to 8 half-lives.

142
Q

Which type of nuclear decay could be detected in an atomic absorption spectrum?

A

Because gamma radiation produces electromagnetic radiation (rather than nuclear fragments), it can be detected on an atomic absorption spectrum

MCAT (9 decks)

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