MCAT Physics

Ohm’s law

V = IR

voltage (volts ) = current (amps) * resistance (ohms)

An increase in voltage will cause a/n (increase/decrease) in current

Increase

An increase in resistance will cause a a/n (increase/decrease) in current

Decrease

STP conditions: pressure

1atm = 760mmHg = 760 Torr = 100,000 Pascals

STP conditions: gas

1mol any gass = 22.4L

STP conditions: temperature

273K = 0°C = 32°F

760mmHg = ____Torr

760

Intensity =

Power / area

Amount of energy emitted / area (time)

Energy of a photon

E = hf = hc/lambda

Index of refraction

n = C / Vm

n = speed of light / velocity in medium

1 Newton =

1kg * m/s²

Torque and work units

Joules

1 Watt =

= J/s = ft*lb/s = kg*m²/s²

1 Joule =

N * m

Power

= force * velocity (Watts)

= W/t

If 5 half-lives have passed, what percentage of the substance will remain?

1 → ½ → ¼ → 1/8 → 1/16 → 1/32

1/32 of the substance has decayed, which means 31/32 of the substance remains.

What assumption can be held about ideal gasses?

Individual molecular volume and intermolecular forces are negligible.

During gamma decay, the nucleus emits:

Photon

Alpha decay

-4 atomic mass

-2 atomic number

+4 / +2 He

Beta- decay

+0 atomic mass

-1 atomic number

Beta+ decay

+0 atomic mass

+1 atomic number

Isotopes vary in the number of:

Neutrons

1 kcal = ___ kJ

4.18kJ

1 amp =

1 Coulomb/second

1 Volt

1 J/C

Newton / Coulomb =

Volt / meter

1 Farad =

1 Coulomb / Volt

1 Tesla

N * s / m * C

1 Newton =

1 Kg * m/s²

1 Joule =

N * m

1 Watt =

J / s = ft*lb / s = Kg*m² / s

1 Hz =

1/s

1 atm =

760 Torr

760 Torr =

1 × 10^4 Pa

0°C =

273K = 32°F

Mol volume of a gas at STP

= 22.4 L/mol

deci

1 × 10^-1

pico

1 × 10^-12

Giga

1 × 10^9

Mega

1 × 10^6

Gas → liquid

Condensation

Liquid → gas

Vaporization

Liquid → solid

Freezing

Solid → liquid

Melting

Solid → gas

Sublimation

Gas → solid

Deposition

Heat of fusion

Change in temp to turn solid → liquid (melting)

Heat of vaporization

Change in temp to turn liquid → gas

Visible light wavelength range

380-750nm

Red light wavelength

650-750nm

Sound travels most rapidly in which medium?

Solids

Nearsightedness

Focal length is too short relative to the length of the eye.

Image of a distant object is:

• In front of retina

• Requires diverging lens correction

Velocity =

Δd/Δt

Acceleration

Δv/Δt

If acceleration = 0, velocity is

Constant; object is moving at a steady speed and direction.

Electromotive force (EMF)

voltage generated by the battery/battery’s full voltage in the absence of any current.

cos(0) =

1

Richness of a sound it most attributed to

The sum of different overtones

Sound travels fastest through

Solids > liquids > gas (air)

Light travels fastest through

vacuum > air > water > glass

Beat definition

Interference of two sound waves at slightly different frequencies (perceived as variations in volume)

Low frequency sounds produce _____ pitches

low

Shorter wavelength =

Higher frequency, higher pitch

Volumetric coefficient of expansion is

3x the linear coefficient of expansion

Electromagnetic spectrum

• Radio: 10³

• Microwave: 10^-2

• Infrared: 10^-5

• Visible: 0.5 × 10^-6

• Ultraviolet: 10^-8

• X-ray: 10^-10

• Gamma ray: 10^-12

RMI VUX G

Mechanical work formula

Work = Fdcos(θ)

Power units

W = J/s

Power (circuits)

= I*V

(current * voltage)

eV

Electron Volt

Amount of energy required to accelerate one single electron over a potential difference of one volt.

Orange wavelength

580-620nm

Yellow wavelength

570-580nm

Green wavelength

490-570nm

Blue wavelength

450-490nm

Indigo wavelength

425-450nm

Violet wavelength

380-425nm

cos(90°) =

0

sin(90°) =

1

cos(0°) =

1

sin(0°) =

0

sin(30°) =

0.5

cos(30°) =

0.9

sin(45°) =

0.7

cos(45°) =

0.7

sin(60°) =

0.9

cos(60°) =

0.5

work =

Change in kinetic energyK

Kinetic energy =

½ mv²

Magnification (m) is _____ proportional to image distance (i) and object distance (o)

Inversely

Magnification equation

= -i/o

Converging (convex) lens: outside focal point

i: +, real

m: -, inverted

o: -, behind

f: -, diverging

Converging (convex) lens: inside focal point

i: -, virtual

m: +, up

o: +, front

f: -, diverging

Diverging (concave) lens

i: -, virtual

m: +, up

o: +, front

f: +, converging

Diverging (concave) mirror focal point

f: -

Converging (convex) mirror focal point

f: +

What type of lens corrects myopia (nearsightedness)?

Diverging/concave

What type of lens corrects hyperopia (farsightedness)?

Converging/convex

If an object is placed in front of a concave/diverging lens, what effect does it have on the image?

None- the object distance for a concave/diverging lens needs to be positive.

A negative image distance (-i) will produce an image on which side of the lens? (for correcting vision)

The side on the other side of the eye.

Refraction index of air (n_air)

1

Refraction index of water (n_water)

1.3