Physics Flashcards

Question

Power

Answer 1

P=W/t | (Watts)

Answer 2

PE and KE conserved

Answer 3

PE is conserved, KE is lost (to sound, light, heat, deformation)

Answer 4

Objects stick together, PE is conserved

Answer 5

W_net=ΔKE

Answer 6

I=FΔt=Δp=m(v_f-v_i)

Answer 7

Work accomplished with reduced force via: inclinded plane, wedge, axel/wheel, lever, pulley, screw

Answer 8

Mech. Adv = F_out/F_in

Answer 9

Efficiency=W_out/W_in

Answer 10

x=(Σm_ix_i)/(Σmi)

Answer 11

ρ_H2O=1g/mL=1kg/L

Answer 12

SG=ρ/ρ_H2O

Answer 13

F_B=weight displaced F_B=(ρ_fluid)(V_submerged)(g)

Answer 14

Y=stress/strain Y=σ/ε

Answer 15

If you apply pressure on a liquid, the pressure is transmitted equally to all parts of the liquid.

Answer 16

P=ρgh+P_atm

Answer 17

Q=AV=dV/dt Q=A(dL/dt)

Answer 18

P + ½ρv² + ρgh = constant

Answer 19

ΔL = αL₀ΔT

Answer 20

Attraction of liquid molecules to another substance

Answer 21

* Resistance of a fluid to flow * Ideal fluid is inviscid

Answer 22

v_c=(Re\*η)/(ρ\*D) * η=viscosity * Re=Reynolds #

Answer 23

B=(F/A)/(ΔV/V)

Answer 24

Periodic motion, particle oscillates about equilibrium, has a linear restoring force

Answer 25

ω=2πf (Hz)

Answer 26

x=Asin(ωt)

Answer 27

KE=½mv² U=½kx²

Answer 28

F=-mgsin(θ)

Answer 29

Particles oscillate along direction of travel of the wave motion

Answer 30

Particles oscillate perpendicular to energy (ex. light, electromagnetic)

Answer 31

T=1/f 2πf=ω

Answer 32

* f is constant, amplitude changes, nodes at rest

Answer 33

* f at which object vibrates when disturbed

Answer 34

Natural frequencies are multiples but not whole # multiples

Answer 35

Periodically varying force applied to a system

Answer 36

* longditudinal * can't travel through a vacuum * speed inversely proportional to (density)^½ * Audible: 20-20,000 Hz * Ultrasonic: \> 20,000 Hz * Infrasonic: \< 20 Hz

Answer 37

I=P/A | (W/m²)

Answer 38

β=10log(I/I_o) [dB]

Answer 39

Amplitude (Greater amplitude = greater energy) (Higher amplitude = higher intensity)

Answer 40

* Resonance is when things oscillate at its maximum amplitude. * Resonance occurs at resonance frequencies.

Answer 41

f_o=f_s(v±v_o)/(v±v_s) * v_o is positive when observer moves towards source * v_s is negative when source is moving towards observer

Answer 42

Materials in which charges can move freely. (ex. metal)

Answer 43

Insulators are materials in which charges can not move freely.

Answer 44

F=kq₁q₂/r² | (k=9E9 Nm²/C²)

Answer 45

Electric field goes from positive to negative Unit: N/C

Answer 46

Radially perpendicular to the wire

Answer 47

V=kq/r V=U/q_o * V is absolute potential caused by q, or experienced by q₀ * U is elec. potential energy posessed by q₀ * Unit: Volts (V) = J/C

Answer 48

ΔV=V_B-V_A

Answer 49

* Places where the potential is the same * Always perpendicular to the electric field lines

Answer 50

* A positive charge and a negative charge separated by some distance * In an electric field, it will align itself with electric field

Answer 51

* Where a charged object induces the movement/redistribution of charges in another object * Static- charged species polarizes non-charged species by being there * ex. comb rubbed against fur- pick up paper with comb

Answer 52

Φ_E=EAcosθ Φ_E=q/ε₀ * Φ_E= electric flux * E = electric field * θ = angle between field and normal of the area * ε₀ is the permitivity of free space

Answer 53

Electric field inside a closed conducting cage is zero (Charges on the conducting cage will rearrange to cancel out any external field)

Answer 54

* B * Exists in a region of space if a moving charge experiences a force due to its motion in that region * Unit: Tesla (T) or (N\*s)/(m\*C)

Answer 55

F=qVBsinθ (RHR: thumb is direction of +q, fingers is direction of B, palm is F)

Answer 56

F=iLBsinθ * i = current * L = length of wire * Currens is direction of moving positive charge * Two wires attract eachother if current is in same direction * Two wires repel eachother if current is in opposite directions

Answer 57

c=3x10⁸ m/s

Answer 58

Yes, light slows down when it travels in another medium

Answer 59

Radiation of oscillating electric and magnetic fields are **mutually perpendicular** to each other and to the **propagation direction**.

Answer 60

Lower frequency waves have **longer** wavelengths, and **less** energy.

Answer 61

causes electronic oscillations in the antenna

Answer 62

cause molecular rotation

Answer 63

Causes molecular vibration

Answer 64

Can excite electrons to orbits of higher energy. Ranges from 400-700 nm. 400nm=violet, 700nm=red

Answer 65

Can break bonds and excite electrons so much as to eject them, which is why UV is considered ionizing radiation

Answer 66

Ionizing radiation, photoelectric effect

Answer 67

**Lower Frequency, Longer wavelength, less energy** Radio Microwave Infrared Visible UV X-ray Gamma rays **Higher Frequency, Shorter Wavelength, More Energy**

Answer 68

* interfering light sources must be coherent (maintain same phase relationship) * Light from 2 slits in Young's double slit experiment are coherent * Light source must be monochromatic (of single color/wavelength)

Answer 69

dsinθ=mλ * Bright bands at m=0, +/-1, +/-2 ... * Dark bands at m= +/-0.5, +/- 1.5...

Answer 70

* Thin films provide a means for interference to occur * Light reflecting off the outer and inner boundary of a thin film interfere with eachother * Film of oil on water appears like a swirly rainbow

Answer 71

* Diffraction= light spreads out after passing through the slit, instead of going in a straight path * Diffraction grating = a slap with many slits close together * Bright and dark bands occur at same locations

Answer 72

* Light through a single slit has a central bright band and maximas and minimas * The equation is different: asinθ=mλ (a= width slit)

Answer 73

Appears as a diffractino pattern of circular bright and dark bands, with a central bright band.

Answer 74

Fringes of bright and dark bands appear above the boundary.

Answer 75

Central bright spot, patterns of dark and bright rings.

Answer 76

Light with electric field oscillating in many planes

Answer 77

Light with electric field oscillating in only one plane

Answer 78

Can rotate polarized light clockwise or counterclockwise

Answer 79

frequency decreases (observer and source move away from eachother)

Answer 80

Frequency increases (source and observe moving towards each other)

Answer 81

* Light Amplification by Stimulated Emission of Radiation * Normal light emission = spontaneous * Laser emission = stimulated emission

Answer 82

* θ_i=θ_r * mirrors completely reflect light * Partial reflection when changing medium

Answer 83

n₁sinθ₁=n₂sinθ₂

Answer 84

Dispersion is the change of index of refraction with wavelength

Answer 85

Blue light refracts mroe than red light in a prism.

Answer 86

* going from medium of high n to low n * angle of incidence \> critical angle * Find the critical angle by: * n₁sinθ_c = n₂sin90° * n₁ \> n₂ θ_c = critical angle

Answer 87

**concave **mirrors focus light, so it's converging. **convex **mirrors can't focus light, so its diverging.

Answer 88

Converging mirrors have **positive** focal length. Diverging mirrors have **negative** focal length.

Answer 89

(1/p) + (1/q) = 1/f (1/o) + (1/i) = 1/f * p is always positive

Answer 90

If q is positive, the image is **real**.

Answer 91

For mirrors, real images are **in front of** the mirror. For lenses, real images are **behind** the mirror.

Answer 92

Focal length (f) is positive when the mirror/lens is **converging**. This is when the mirror is **concave** or the lens is **convex**.

Answer 93

* Real images are inverted and can be cast on a screen * Virtual images are always erect and can't be cast on a screen.

Answer 94

For concave mirrors, real images, (positive q) are formed **in front of** the mirror.

Answer 95

For convex mirrors, images are always **virtual**. (negative q)

Answer 96

**Diverging** mirrors and lenses (**convex mirrors and concave lenses** can never form real images.

Answer 97

Convex lenses are the same as **concave** mirrors, both are **converging**. Except: * Real images are on the opposite side of the lens as the object because light travels through the lens and can focus on a screen behind the lens. * Virtual images are on the same side of the lens as the object.

Answer 98

Concave lenses are the same as **convex** mirrors (both are **diverging**). Except: * A virtual image formed by the lens is on the same side as the object because light can't focus in front of a lens and be cast on a screen.

Answer 99

Converging lens is **convex.**

Answer 100

Diverging lens is **concave**.

Answer 101

P=1/f | (P in diopters)

Answer 102

Not all light will focus at the focal point

Answer 103

Blue light gets refracted more than red light, so different colors focus differently.

Answer 104

* **Diverging (concave)** for near-sightedness * **Converging (convex)** for far-sightedness

Answer 105

* Electron orbits the pos nucleus * Electrostatic attraction pulls electron to nucleus * Electron orbits at high speed to prevent crashing into nucleus * electron orbits at different energy levels (n) * Higher energy level = larger radius

Answer 106

It emits electromagnetic radiation. Emission spectrum of hydrogen consists of sharp, distinct lines.

Answer 107

E=-13.6eV/n² (E is energy, n is energy level) (All energies are negative- energy contributes to the stability of the system)

Answer 108

it is less stable in orbit and it is easier to knock out the electron

Answer 109

0 eV, no binding energy, the electron dissociates

Answer 110

Z is the atomic number. (Higher Z values give more negative, and more stable energies)

Answer 111

R is rydberg constant, nf and ni are final and initial energy levels

Answer 112

E=hf=hv=hc/λ

Answer 113

Energy is emitted for transitions to **lower** energy levels.

Answer 114

Number of protons. What defines an element.

Answer 115

Number of protons.

Answer 116

The weighted average of the atomic mass for all isotopes.

Answer 117

Atomic mass = number of protons + neutrons

Answer 118

Neutral particles in the nucleus

Answer 119

Positive particles in the nucleus.

Answer 120

Things with same # protons, different # neutrons.

Answer 121

proton or neutron

Answer 122

strong force

Answer 123

Due to electrostatic repulsion between positively charged protons in the nucleus.

Answer 124

The strong force or nuclear force is much stronger than electromagnetic repulsion.

Answer 125

Ejection of a helium nucleus at a relatively low speed.

Answer 126

In a nearsighted (myopic) individual, the image of a distance object is focused **in front of** the retina, requiring **divergent** lens correction. * Nearsighted person cannot clearly see objects far away * Nearsighted eye has a shorter focal length

Answer 127

SG=ρ_sample/ρ_h2o

Answer 128

6.02x10²³

Answer 129

Energy only. Mechanical waves, such as sound and water waves, are a local oscillation of material. Only the energy propagates; the oscillating material does not move far from its initial equilibrium position.

Answer 130

Ejection of a high-speed electron/positron.

Answer 131

Release of high energy electromagnetic wave.

Answer 132

Weakest form of radiation. Can be stopped by a sheet of paper. Essentially a low-speed helium nucleus.

Answer 133

More energy than an alpha particle. Can be stopped by aluminum foil. High speed electron. (Or positron)

Answer 134

Strongest form of radiation. High Energy electromagnetic wave. Can be stopped by a hick layer of lead or concrete.

Answer 135

The more unstable something is, the **shorter** the half life

Answer 136

For exponential decay, a semi-log plot is a straight line with a **negative** slope. The semi-log plot intercepts the x-axis where the original y value is **1.**

Answer 137

Two nuclei coming together. (The sun works by fusion- hydrogen fuses to form helium)

Answer 138

M_nucleons=M_atom+binding energy/c² M_nucleons\>M_atombecause some is converted to binding energy

Answer 139

ΔM=M_nucleons-M_atom | (Also called mass defect)

Answer 140

Binding energy = ΔMc² | (Energy liberated is binding energy)

Answer 141

Energy is liberated when mass is **lost** during a reaction. Energy is absorbed when mass is **gained** during a reaction.

Answer 142

* Nuclear binding energy (binds nucleons together) * The Strong Force

Answer 143

Strongest: Iron (Fe 56) Weakest: Deuterium (2-nucleon isotope of hydrogen)

Answer 144

**I=ΔQ/Δt** Direction = flow of positive charge Unit = C/s

Answer 145

* Electromotive force, a potential difference, unit: V * Battery is a source of emf * Battery w/o internal resistance has potential difference = EMF * Battery w/ internal resistance: potential difference = EMF - voltage drop

Answer 146

the voltage across the terminals of a battery. Terminal potential = EMF -IR_internal

Answer 147

I_series=I₁=I₂=I₃ V_series=V₁+V₂+V₃

Answer 148

V_parallel=V₁=V₂=V₃ I_parallel=I₁+I₂+I₃

Answer 149

* ρ = RA/L * Inverse of conductivity * Greater resistivity = greater internal resistance

Answer 150

C=Q/V=εA/d

Answer 151

U = Q²/2C = ½QΔV = ½C(ΔV)² ## Footnote

Answer 152

**Series:** 1/C_eq = 1/C₁ + 1/C₂ + 1/C₃ **Parallel:** C_eq = C₁+ C₂ + C₃

Answer 153

Nonconducting material. Inserting a dielectric between the plates of a capacitor increases the capacitance by either increasing Q, or decrasing V. V = V₀/κ C = κC₀

Answer 154

* **Electrolyte concentration** * **Temp** * conductivity decreases when metal temp increases, conductivity increases when semi-conductor temp increases * Extremely low temperatures= superconductivity = 0 resistance

Answer 155

Resistivity.

Answer 156

I_rms = I_max/√2 = 0.7 I_max V_rms= V_max/√2 = 0.7 V_max V_rms = I_rmsR