Uworld Physics

How do you find the magnitude of an electric field?

1. change in voltage/distance 2. This is the voltage across the electric field/ distance of the field

How can you find the specific gravity of a substance?

1. density of substance/ density of water 2. This should also help you find the density of things as well

What is the difference between a closed system and an isolated system?

1. in a closed system, heat can be exchanged but matter CANNOT 2. In an isolated system neither heat nor matter can be exchanged

How do you deal with the total capacitance of capacitators in series or parallel?

1. in parallel: add them like normal 2. in series: add their 1/capacitator

How do you measure intensity of sound?

1. power (energy per unit time)/area === p/A 2 p = E/t

What is viscosity?

1. the resistance of a liquid to flow 2. Also known as the shearing force of a liquid 3.Kinetic energy is dissipated by the viscous shearing force acting between different layers of a fluid

The direction of a magnetic force of a moving ion is perpendicular to what?

1. the velocity of the moving ion 2. direction of the magnetic field 3. Use the right hand rule to do this: thumb is the force, pointer finger is the direction of the magnetic field, and the second finger underneath is the direction of the current.

What is the index of refraction of air?

1.0003

What is the relationship between frequency and wavelength?

1.Frequency (f) and wavelength (λ) are joined by the equation fλ = c, where c is the speed of light. As the speed of light is constant, if you increase the frequency, the wavelength must decrease to maintain this equation and vice versa 2. C = 3*10^8 m/s

What is hydrostatic pressure?

1.Pressure exerted by the weight of a fluid

What is the volumetric flow rate?

1.Volume of blood passing a point per unit of time 2. VFR (Q) = area (A) * velocity (V)

What wavelengths are within the visible spectrum?

750 - 400 nm

What is 1 atm equal to?

760 mm Hg

What is a linear polarizer?

A linear polarizer selectively allows certain orientations of polarized light to pass through. You can turn a linear polarizer so that it allows only vertically polarized light though, or you can turn it another at 90° to allow only horizontally polarized light

Another capacitor, identical to the original, is added in series to the circuit described in the passage. Compared to the original circuit, the equivalent capacitance of the new circuit is A. 1/2 as great B. the same. C. 2 times as great D. 4 times as great

A. 1/2 as great

A student has a thin copper beaker containing 100 g of a pure metal in the solid state. The metal is at 215°C, its exact melting temperature. If the student lights a Bunsen burner and holds it for a fraction of a second under the beaker, what will happen to the metal? A. A small amount of metal will turn to liquid, with the temperature remaining the same B. All the metal will turn to liquid, with the temperature remaining the same C. The temperature of the metal at the top of the beaker will increase D. the temperature of the whole mass of metal will increase slightly.

A. A small amount of metal will turn to liquid, with the temperature remaining the same Melting occurs at a constant temperature because a certain amount of energy, the latent heat of fusion, is needed to convert a substance from its solid to liquid state. The temperature of the metal will not increase above its melting point until all of the metal has melted. The small amount of heat supplied by the bunsen burner is insufficient to melt 100 g of the metal but could melt a small amount of the metal at the constant temperature of the melting point. Thus, answer choice A is the best answer.

Compared to other diffraction techniques, the advantage of x-ray diffraction is that it enables: A.determination of three-dimensional molecular structure. B.determination of the work function corresponding to each electron. C.measuring the wavelength of electromagnetic radiation. D.measuring the linear polarization of light.

A.determination of three-dimensional molecular structure. X-rays diffract within molecules because the space between atoms is comparable to the wavelength of x-rays. X-ray diffraction through a sample of a purified and crystallized material can be used to determine its three-dimensional molecular structure and packing.

What is an isochoric process?

Also known as isovolumetric, in which volume of the system does not change

An 8-F parallel plate capacitor generates a voltage of 5 V when fully charged. How much charge is stored by the capacitor?

Answer: 40 C The equation you need here is Q = VC (Q: Charge on plate, C: capacitance, V: voltage) Capacitors generate electric potential (voltage) by storing charge. The quantity of charge stored by a capacitor is a product of capacitance (capacitor strength) and the voltage generated by charge storage

What is the pressure required to compress a normal bone sample by 1.5 mm? (Note: The cross-sectional area of bone samples used in the experiment is 10 mm^2) A.1.10 kN/mm2 B.1.50 kN/mm2 C.110 kN/mm2 D.150 kN/mm2

B. 1.50 kN/mm2 P = F/A P = 15/10

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 kinetic energy of the electron upon reaching the anode compare to its initial potential energy immediately after it has been ejected? A. It will be 2 times as large B. It will be approx. equal C. It will be 1/4 as large D. It will be 0

B. It will be approx. equal 1. First you need to understand that when an electron is initially ejected all the energy is coming from potential energy. As the electron moves from the cathode to the anode, the PE is being converted to KE 2. Now, the test maker is specifically stating the the energy of the electron is slightly higher than the work function (in terms of background energy of electron = energy of photon - work function). This indicates the PE =. KE

If the speed of the charged particle described in the passage is increased by a factor of 2, the electrical force on the particle will: A. Decrease by a factor of 2 B. Remain the same C. Increase by a factor of 2 D. Increase by a factor of 4

B. Remain the same Electrical force depends on the particle's charge and the strength of the electric field experienced by the particle, not on the particle's speed. Thus, B is the best answer. E (electrical field in Newtons/coulomb) = F (electrical force in Newtons) / q (charge) It seems A/C are directly opposite to one another and that may be an indication to remove it.

Ultrasonic shock wave devices may be used in medical settings to disrupt disease structures located deep in the body. Among other variables, the device user can control the frequency of emitted waveforms. The adjustment of waveform frequency: A.can be used to provide direct auditory feedback to the user. B.enables high-amplitude resonance within diverse target tissues. C.may eliminate the attenuation effects associated with tissue interfaces. D.assists in the measurement of bodily fluid velocity.

B. enables high-amplitude resonance within diverse target tissues. C is incorrect bc you can never eliminate attenuation, differing tissue types will always attenuate sound waves A is incorrect bc shock wave ultrasound utilizes ultrasonic waves that transmit at frequencies beyond the human auditory spectrum, making direct auditory feedback from the device to the user impossible D is incorrect bc doppler ultrasound is a specialized imaging technique that allows for the characterization of dynamic structures. However, shock wave ultrasound is typically used to destroy static structures Shock waves are good bc they also do not defract as easily due to the extremely small wavelengths.

What expression gives the wavelength of the third harmonic for a 1.5 m pipe that is closed at one end? A.(2) × (1.5) / 3 B.(4) × (1.5) / 3 C.(2) × (1.5) / 5 D.(4) × (1.5) / 5

B.(4) × (1.5) / 3 Equation you need to know for this: λn=4L/n (where n is an odd numer) Pipes closed at one end cannot produce even-numbered harmonics (n = 2, 4, 6...), as no displacement of air takes place at the closed end. In other words, the closed end of the pipe is always a node (ie, a point of minimum displacement) and the open end of the pipe is always an antinode (ie, a point of maximum displacement).

A flask with height h and base area A is filled with water. If the pressure due to the weight of the water is 2 atm halfway between the base and the top, what is the pressure due to the weight of the water at the base of the flask A.1,500 mm Hg B.3,000 mm Hg C.4,600 mm Hg D.6,000 mm Hg

B.3,000 mm Hg 1. First identify the equation you need for a pressure equation: P = ρgh 2. At the halfway point the pressure is 2 atm therefore: 2atm = (1) (10) (h/2). This means that h = 4atm/10 3. At this point just plug and chug

Circularly polarized light results from the vector sum of the electric field oscillations of two linearly polarized transverse waves traveling along the same axis. To achieve circular polarization, the two transverse waves must be out of phase to one another. The necessary phase difference is: A.0° B.90° C.180° D.360°

B.90° If the polarized light are 90 degrees out of phase, the will seem circular to the person observing it

Which of the following experimental groups would aid in determining if the procedure described in the passage has a confounding variable? A.Group with laparotomy used without measuring blood pressure B.Group with minimally invasive aortic catheterization to measure mesenteric blood pressure C.Group fitted with noninvasive tail cuffs to measure systolic blood pressure D.Group with laparotomy to measure renovascular blood pressure

B.Group with minimally invasive aortic catheterization to measure mesenteric blood pressure A/D are kind of the same so you can cancel those The tipping point here is between invasive and non-invasive. The latter would not be confounding.

When standing barefoot on a floor, body heat is transferred into the floor based on the thermal conductivity k of the flooring material. The heat flow rate per unit area H is defined by: H=k (ΔT/L) where ΔT is the difference in temperature over a distance L. The tiled part of a floor in a room at room temperature feels colder than the carpeted part because A.the temperature of the tile is lower than the temperature of the carpet. B.the thermal conductivity of the tile is higher than the thermal conductivity of the carpet. C.the thermal conductivity of the tile is lower than the thermal conductivity of the carpet. D.heat travels a greater distance through the carpet.

B.the thermal conductivity of the tile is higher than the thermal conductivity of the carpet. For a person straddling the tile and carpet, the temperature gradient between the body (37° C) and each object is the same because the carpet and the tile are at the same temperature (room temperature 20° C). Heat flows from the warmer body to the cooler objects. However, tile is a better thermal conductor than carpet and therefore has a higher k. Consequently, heat transfer from the body to the tile is more rapid than the heat transfer to the carpet such that the person perceives the tile being colder than the carpet

How can you calculate the capacitance of parallel capacitators?

C = k * A/d k = is a constant for the material. The dielectric constant for air is very close to 1 so if the capacitors are in a vacuum you can assume K is 1. K changes with the insulating material between the two plates of the capacitors. As the distance between the capacitors increase, capacitance decreases.

A concave mirror has a 4-m radius of curvature. This mirror will focus distant objects at a location that is approximately A.4 m in front of the mirror. B.4 m behind the mirror. C.2 m in front of the mirror. D.2 m behind the mirror.

C. 2 m in front of the mirror. f = r/2; the focal length determines where the image is located. For concave mirrors the image is always in front (for convex the image is always at the back)

Which of the following occurs when electrons are ejected from the cathode? A. The voltage across the electrodes reverses polarity B. The voltage difference between the electrode increases C. Current flows through the circuit D. The total resistance of the circuit increases.

C. Current flows through the circuit Option A would ruin the battery, D there is no indicator of a resistor, B only occurs if there is an increase in current, which often results from an increase in voltage Definitionally, current is simply the movement of electrons, which is totally happening in this question

Which change would result in the greatest decrease in the volumetric blood flow rate within a mesenteric vessel? A.Decrease the viscosity of the blood by a factor of 4 B.Increase the length of the vessel by a factor of 9 C.Decrease the radius of the vessel by a factor of 2 D.Increase the pressure difference by a factor of 6

C. Decrease the radius of the vessel by a factor of 2 1. volumetric flow rate (Q) = flow velocity * cross sectional area 2. This indicates that changes in area can alter the flow rate—so in the case of blood vessels changing the area would do this.

An ideal fluid flows through a tube at an initial speed of 4.0 m/s. What will be the speed of the fluid if the cross-sectional area of the tube decreases from 6.0 m2 to 2.0 m2? A.1.3 m/s B.4.0 m/s C.12 m/s D.36 m/s

C.12 m/s Use the continuity equations A1v1 = A2v2

Which of the following can be used as units for η in R=8ηL/π(r^4)? Use the following equations as well: ∆P = QR. A.Pa⋅m2⋅s B.Pa⋅m^2/s C.Pa⋅s D.Pa/s

C.Pa⋅s 1. With questions like this it is important to decide how we can isolate the variable under consideration. We can do this by equalling R in both equations to each other: 8ηL/π(r^4) = ∆P/Q. 2. Now replace all the variables with their units: η(m)/(m^4) = Pa/(m^3/s).

The spherical aberration of a converging lens can be corrected by reducing the thickness of the lens periphery. The spherical aberration of the lens is caused because light rays emerging from the lens: A.are insufficiently refracted at the lens periphery. B.converge at the lens focal point uniformly. C.are excessively refracted at the lens periphery. D.are scattered due to chromatic dispersion

C.are excessively refracted at the lens periphery. Looking at the answer choices, A and D are directly opposite to one another, usually this is a sign one of them might be the answer. Also this is a knowledge based question as well—Spherical aberration describes the phenomenon by which real lenses' perfectly rounded (ie, spherical) surfaces do not produce an image at a single point, but rather at a series of focal points. Because reducing the thickness of the lens periphery will lead to less refraction of light, light rays exiting the periphery of a spherical converging lens can be said to refract excessively, converging on a focal point that is too close to the lens.

What is capacitance?

Capacitance is the measure of an object's ability to store an electric charge. Any body capable of being charged in any way has a value of capacitance. Capacitors can store energy when a battery or voltage source is connected

How does circular polarization occur?

Circular polarization occurs when two wave forms with equal amplitude and perpendicular linear polarization (ie, polarized along different axes) propagate 90° out of phase to one another (ie, one waveform yields zero displacement when the other waveform is yielding a peak or a trough). The mismatch in phase causes each contributing wave to generate momentary oscillations that are different at every point in time. This results in a continuous rotation in the orientation of the combined wave

What is current and how does it differ from voltage?

Current is the movement of electrical charges. Current is always conserved, unlike voltage, so the current coming in is the same as the current leaving

Increasing the frequency of each photon that is directed at the cathode will: (Energy of proton = h * frequency) A. Decrease the number of photons ejected B. Increase the number of photons ejected C. Decrease the speed of the ejected electrons D. Increase the speed of ejected electrons

D. Increase the speed of ejected electrons This will require you to understand the how the photoelectric effect works. In this effect photons are shot at the cathode so that they release an electron which then accelerates towards the anode. This automatically makes A/B incorrect. Now you can look at C/D. If you increase the frequency of the photon, you also increase its energy. This means that the electrons are better able to overcome the work function of the metal that is preventing it from leaving. This increase in energy will increase the energy of the potential energy of the electrons, which also therefore increase its kinetic energy

What is power?

Energy expended / time

How do you find the force exerted on a particle in a uniform electric field?

F = qE (particle charge * electrical field strength)

How do you calculate the buoyant force?

Fb = density of displaced fluid * Volume of displaced fluid * gravitational force.

How can you find current from charge?

I = Q/t : Q is the charge that passes through a given point in time (t)

The locations of the bright and dark bands produced by light passing through a single slit depends on the: I. initial light intensity. II. slit width. III. wavelength

II and III (slit width and wavelength) The light intensity is determined by the slit width and wavelength. If the wavelengths are out of phase (which are usually integer multiples ( +/- 1, +/-2, ....))

Which of the following best describes the movement of an electron after it is ejected from the cathode?

IT accelerates towards the anode, as the potential energy of the electron is being turned to kinetic energy

What is the function of an ammeter?

If places in series it usually measures current

What is magnification? And, how do you find the magnification of a multi-lens system?

Magnification is the phenomenon in which a lens produces an image that is enlarged or shrunken relative to the original object 1. You find the magnification of a multi-lens system by multiplying all the magnifications. Ex. Mtotal = M1 * M2*M3.....

How can you find electrical power?

P = IV = I^2 *R = V^2/R

How do you calculate power?

Power= work/time or Energy/time

How can you calculate the charge of each plate in a capacitor pair?

Q = VC Q: Amount of energy stores in one capacitor (+Q on one place -Q on the other) V: Potential difference between the two plates C: Capacitance of the capacitator

What is torque?

The ability of a force to cause rotation around an axis.

What is the absolute temperature of a system proportional to?

The absolute temperature scale quantifies temperature relative to absolute zero, the lowest possible total energy of matter. The absolute temperature of any system is directly proportional to the average kinetic energy of molecules within the system

What are wavelengths or harmonics like?

The first harmonic always has the longest wavelengths, but subsequent harmonics will decrease in wavelengths Because frequency and harmonics are inversely proportional, as the harmonic increases so do the frequency

What is the focal length of a concave mirror?

The focal length (f) of a concave mirror is the distance in front of the mirror at which reflected light rays converge to form an image F = r/2 (this equation is the same for a concave mirror) -- r is the radius of curvature

How does the speed of sound and frequency difference between mediums?

The speed of sound v changes in different mediums (eg, different tissues in the body) due to variations in the physical properties of the medium, but the frequency f of the sound wave remains constant

What is the voltage for parallel circuits?

The voltage across parallel circuits are the same

What is the adiabatic process?

There is no heat exchange between the system and the environment

In an oscillatory object how do you calculate potential energy?

U = 1/2 * k * x^2 Here x is the displacement, max displacement = max PE

What is pressure-volume work?

W = external pressure applied to system * change in volume W = Pa * m^3 = Joules

A force of 50 N is used to push a wheelchair forward at constant velocity. If the wheelchair is displaced 0.5 m each second, what is the mechanical power expended when transporting the wheelchair? A.13 J B.25 W C.100 W D.200 J

When you get a question about power, immediately think of the equation P = W/t = P = F*d/t = F*v Power is indicated through watts This is a plug and chug problem. B.25 W

How do you find the wavelength of standing waves?

Where n is 1,2,3,4..... based on the harmonic At each end of the standing wave is an antinode

What is Columb's law?

a law stating that like charges repel and opposite charges attract, with a force proportional to the product of the charges and inversely proportional to the square of the distance between them.

What does Bernoulli's principle state?

as the speed of a moving fluid increases, the pressure within the fluid decreases

How can you find the fraction of a solid submerged in liquid?

density of solid/density of water

What is deposition?

gas to solid

What is Snell's Law?

n1sinθ1 = n2sinθ2

What are characteristics of an ideal fluid?

no viscosity, incompressible, lack turbulence, and they experience irrotational flow

What is the equation for pressure of fluids?

pressure = force/area P = F/A

In EM spectrum classify waves with the largest to smallest wavelengths?

radio > microwaves > infrared > visible light >UV > X-rays > Gamma

What is wave velocity?

speed of the wave (v = wavelength * frequency)

What is voltage?

the difference in electrical potential between two points that drives the movement of electrical charge.

How do you calculate elastic potential energy?

1. 1/2 x spring constant x extension squared

What is capacitance and how do you calculate the energy in a capacitator?

1. Capacitance is the ability of a capacitor to store charges. Units are in Faraday 2. The amount of energy (U) stored in a capacitor depends on the capacitance (C) and the voltage (V) stored across its plate 3. U = 0.5 *C *V^2

What is the difference between incompressible and compressible fluids?

1. Compressible fluids: their volume can change over time 2. Incompressible fluids: the mass the enter from one portion is the same mass the leaves at a different portion. This means that the volume does not change over time, but the area and velocity can. This is expressed by the continuity equation: A1V1 = A2V2

Imagine you create a bomb calorimeter with an ice bath, instead of its typical room temp water bath. How would the temp be affected?

1. Due to latent heat of fusion, the temperature would not change as quickly because the ice would need to all melt in order for the temperature to rise.

How do you find the energy of a photon?

1. E=hf 2. H is plank's constant 3. E is the energy of a photon

What is the magnitude of the electric field of a detector that contains electrodes 3 cm away from each other with a 5V charge.

1. Electrical field can be calculated as Volts/Meter 2. EF = 5V/0.03 = 166.7 V/m

How do you find the power it takes to lift a weight (75kg) from the ground straight up 1 meter in 1 second?

1. First understand that P = work/time 2. In this case work is gravitational potential energy = mgh 3. W = 75*10*1 = 750 4. P = 750 N/ 1 second = 750 W

A charged particle with a mass of m and a charge of q is injected midway between the plates of a capacitor that has a uniform electric field of E. What is the acceleration of this particle due to the electric field?

1. First you need to identify how to calculate the force of a charge in an electric field. Which is..... F = qE (where q is charge and E is electric field) 2. Also the general equation for force is F=ma 3. Equal it to each other to find a. ma = qE, therefore a = qE/m

If you are given a graph with the y axis being Force (kN) and x-axis being Compression (mm), how can you calculate the spring constant?

1. Firstly Fel=−kx : the force elastic for a spring is -kx, where k is the slope of change in force/change in compression

`What is heat and how is it transferred?

1. Heat flow from high temperatures to low temperatures 2. Heat can be transferred by CONDUCTION, or direct physical contact 3. Can be transferred by CONVECTION, of the flow of fluids. Fluids absorb heat from hotter regions and transfer it to colder regions. 4. OR by RADIATION, or the emission of electromagnetic energy

What is heat capacity?

1. Heat required to raise the temperature of an object by a certain unit of temperature: C = mc (Heat capacity = mass * specific heat). When there is a change in temperature then C = q/change in temperature Heat capacity (how much heat to add to a system to change its temperature) 3. q = m*c*(change in temp)

What is pressure?

1. IT is a form of work if there is a change in distance 2. F * d = pressure 3. P = Force/ Area

How are angles of refractions impacted by density?

1. If the density of the second medium (on the bottom) is higher than the one on top, the light will bend toward the normal line (this is the dotted perpendicular line). The opposite is true is the bottom medium is less dense.

How do you calculate mechanical work?

1. Mechanical work describes the transfer of energy that occurs through the application of a force (F) to move an object over some distance (d) or the application of pressure (P) over some change in volume (ΔV) W=F⋅d=P⋅ΔV

An astronaut on Earth notes that in her soft drink an ice cube floats with 9/10 of its volume submerged. If she were instead in a lunar module parked on the Moon where the gravitation force is 1/6 that of Earth, the ice in the same soft drink would float?

1. Regardless of the change in gravitation, 9/10 of the ice cube will float. 2. Let's visualize the forces acting on the cube: Gravitational force mg and buoyant force ρVg, where V is the amount of ice submerged. 3. Bc the ice is not moving you can equal the two forces and you find the following : mg = ρVg. You see there that gravitational forces cancel out and have no affect on how much of the ice is submerged

What are state and path functions?

1. State functions: aka state quantities. Does not depend on the path taken to determine a specific value. Describe the equilibrium state of a system Eg. pressure, volume, and temperature 2. Path functions: aka path function. Depends on the path taken to reach a certain state. The path has taken from one equilibrium state to another. Eg. heat

What is the Ohm law for flow?

1. States that a change in pressure is directly proportional to resistance. 2. a pressure drop across a pipe is directly proportional to the resistance (if the the volumetric flow rate, aka Q, is constant)

How is height related to temperature? (thermal expansion equation)

1. The change in length = coeff of thermal expansion * length * change in temp (replace L with V is you are looking at a change in volume as it relates to temperature

What is internal energy of a system?

1. The definition for this comes from the first law of thermodynamics 2. The change in internal energy is the sum of the heat transferred to the system and the work done on the system by the surrounding 3. E internal=Q+W 4. E internal = total internal energy of a closed system Q = heat W = work done on gas

A cube with a side length of 5 cm floats on the surface of water. If 4/5 of the cube volume floats above the surface of the water, what is the density of the cube? (Note: Density of water = 1,000 kg/m3.)

1. The density of the cube is 200 kg/m3 2. This is pretty simple density of object/density of water is how you determine how much of the object will be submerged in the water 3. Bc 4/5 is not submerged, this means 1/5 is submerged. Using proportions you can answer this question

What is the force exerted on a moving particle in a magnetic field?

1. The force is known as the magnetic Lorentz Force 2. Product of particle's charge, velocity, and strength of the magnetic field.

What does the real image of a concave mirror look like and how does that compare to the convex mirror? Why?

1. The real image of a concave mirror is inverted and is placed in front of the lens 2. The image reflected by a concave mirror is always an upright virtual image 3. The image is present at the focal point calculated by f = r/2 (where r is the radius of curvature of the mirror) 4. For concave mirror the image is in the front, for convex mirrors the image is in the back.

Ultrasound imaging at 1.8 MHz is used to evaluate liver disease. The ultrasound signal travels through a boundary between liver and fat tissue at an angle of 30° relative to the normal at the boundary. If the ultrasound signal has a wavelength of 0.8 mm in fat tissue, what is the speed of sound in fat? A.720 m/s B.1250 m/s C.1440 m/s D.1660 m/s

1. There is a lot of information in this question. Some of which don't matter. But when looking at the question identify an equation you will need: v=λf 2. You are given frequency (which does not change medium to medium) and wavelength in fat. This will allow you to find the speed of the sound in fat. 3. Answer : C.1440 m/s

How can you calculate the fluid flow rate through a closed conduit?

1. Using the volumetric flow rate equation (Q) 2. Q = A * v (cross sectional area * velocity of the fluid)

What is the difference between volumetric flow rate and flow velocity?

1. Volumetric flow rate is the cardiac output (in regards to the heart) or the area * velocity. 2. Flow velocity is the v in VFR

What is the difference between a magnetic and electrical field?

1. a magnetic effect is caused by moving electric charges while an electric field is caused by stationary charges 2.An electric field is essentially a force field that's created around an electrically charged particle. A magnetic field is one that's created around a permanent magnetic substance or a moving electrically charged object

What is an electric field?

1. a space that exerts a force on charged particles 2. In Newtons/Columbs which is equivalent to Volts/m

What are electric field lines? Which direction do they usually point?

1. a way to visualize an electric field. 2. Electrical fields are used to denote the direction a positive charge would accelerate in an electrical field, so electrical fields move away from the positive end and towards the negative end of metal

What is power?

1. amount of work done over time 2. W/t