Physics - Q bank

electric field equation -

volts / meter

frequency equation -

speed of light / wavelength

Constructive interference =

waves add = in phase = 0° or 360°; peaks + peaks

Destructive interference =

waves cancel (moving in opposite directions)= out of phase by half a cycle = 180°; peaks + troughs

The tone with the shortest period has the

shortest wavelength

the time it takes for one complete cycle, oscillation, or wavelength to pass a fixed point

period

Period (T) =

time for ONE full cycle to pass a point

harmonic relationships:

1 harmonic: frequency ? period?

2 harmonic:

3 harmonic: frequency ? period?

1 harmonic- lowest frequency, highest period

3 harmonic- highest frequency, lowest period

if frequency doubles what happens to period?

it doubles

If a wave has frequency = 5 Hz

What is the period?

period (T) = 1/f

Answer: 1/5

If the first harmonic has a frequency of 100 Hz, then what would be the frequency of the second harmonic

200 Hz

Each wave =

harmonic

decipher this graph

the first harmonic is the smooth one, which has the longest wavelength, but shortest frequency

the 2nd harmonic is the one that has slight breaks in it

the third harmonic is the one with a bunch of dotted lines and as the shortest wavelength, but highest frequency

_____ - how many wiggles

_____ - how fast cycles repeat

_____ - how tall the wave is

frequency, period, amplitude

Doppler effect depends on:

relative velocity (how fast they are moving apart (or together)

in terms of the doppler effect

moving toward each other would cause what to happen

frequency to decrease

in terms of the doppler effect

moving away from each other would cuase whwat to happen

frequency to decrease

The velocity of sound is_____ than that of electromagnetic radiation,

much smaller

A receiver is in a jet flying alongside another jet that is emitting 2.0 x 10⁶ Hz radio waves. If the jets fly at 268 m/s, what is the change in frequency detected at the receiver?

how would i figure out this answer?

the jets are flying at the same speed so there is no frequency shift

The floating ice cube implies that its

weight is balanced by the buoyant force on it

pressure equation

P = density x gravity x depth

Law of Reflection:

angle of incidence = angle of reflection

When light reflects off a surface…

How are θ and θ′ related?

they are equal; θ = θ’

If light hits a mirror at 30°, what angle does it reflect at?

30 degrees

what is the assume index of refraction of air

1

what direction is the incidence moving in this and what does it tell us

lower incidence (air) to higher incidence (medium) which means it bends toward normal and is bigger then the incidence angle (a)

Incident ray =

incoming ray

describe reflection

θ - angle of incidence

θ' - angle of reflection

θ' = θ

if problem goes from lower incidence to higher incidence, then light is going into a denser medium and it bends towards normal. and θ is greater then a.

what is the movement of ELECTRONS

cathode → anode

in electrochemistry cells like galvanic or electrolytic cell how to ions move

from anode → cathode

electric force equation:

F = qE
q = charge of particles

E = electric field

If you insert a dielectric what happens to ε

in increases and so does capacitance

capacitance equation

C = eA/D

e is constant in a vacuum

A - area of plates

D - distance between plates

What is the acceleration of this particle due to the electric field?

what equations would you pull out from this equation?

F = ma. and electric field force; F = qE (q - charge, E - electric field)

note the different types of capacitators

in series; 1/C1 (capacitance decreases)

in parallel: C1 + C2 + C3…

potential energy of an oscillatory motion or spring

½kx²

x = displacement (change in objects position)

how would you do 10⁷/10⁹

7 - 9 = 10^-2

what is the conservation of energy.

potential energy is converted into kinetic energy

For a pipe closed at one end, which n values are allowed?

only odd numbers

if order for something to do a different amount of work it would have to

experience a change in magnitude

log⁡₁₀(x)=12
means

x = 10¹²

every 10 dB increase means

10 x more intensity

work formula

Work →

adds energy → potential → kinetic

What is the shortcut formula for maximum height when something is launched straight upward with speed vvv?

v² / (2g) . because you set PE = KE

if something is thrown, at the top of the motion, what are:

• KE =

• PE =

Ke = 0, PE = maximum height. KE = PE when launched

a doppler effect can only occur when

something is moving

The focal length of the mirror depends only on

the radius of the curvature

If velocity = 0 what would this mean about frequency

since there is no motion, there is no frequency shift and frequency = 0

The focal point is:

the place where parallel rays meet (converging) or appear to come from ( diverging)

focal point of converging =

real point

focal point of diverging lens=

virtual point behind the mirror

Focal length =

distance from mirror → focal point

focal length equation

f = r/2

r = radius

Flatter mirror → bigger R

a mirror becoming more curved does what to the radius

decreases it

When light goes from air (low density) → glass (high density) how does light bend

to the normal

snells law :

n1 sin θ1 = n2 sin θ2

n=index of refraction

θ= angle of incidence

Diverging lens:

light rays spread out, convex mirrors, virtual image

Converging lens:

light rays come together, concave mirrors, real image

Ohms Law :

I = V/R

As charge increases, voltage across capacitors

increases

When a capacitor is fully charged: What is the current?

0 (a fully charged capacitor acts like an open circuit)

during the discharge phase what is happening

the capacitor is losing charge and voltage is decreasing

resistance equation

R = V/I

pressure equation

pressure = density x gravity x height

to find doppler effect what do you need

emitted frequency, observed frequency, and speed of sound

If the index of refraction increased A LOT, wha twould happen?

the image would move more

Higher n →

more bending → image moves more

lower n →

less bending → image moves less (closer to original)

A magnetic field only affects:

charged particles

what is the charge of alpha decay

positive

What determines how much a particle bends in a magnetic field?

Charge-to-mass ratio q/m.

beta bends the most because it has the smallest mass

what is the charge of beta decay

B- = electron = -1

dividing two densities gives you what

the density below the surface ONLY , it is not the distance above the surface

list all the decays

alpha - atomic mass decreases by 4 and atomic number decreases by 2

beta minus decay - moves right on periodic table

beta plus decay- moves left on perioidic table

gamma decay - no change, just a release of electrons