P202 quizzes
A lightbulb draws a 0.3 A current from a 1.5 V battery. Its resistance is [?].
5 ohms R = V/I = 1.5V / 0.3A
A 12V battery has a C = 5μF capacitor connected to it. What will be the charge (Q) build up on the capacitor plates?
6x10^(-5) C Q = CV = (5x10^(-6) F)(12 V)
A 6 ohm and a 4 ohm resistor is connected to a 12V battery in parallel. Find the voltage across the 4 ohm resistor.
12V -- the voltage across each resistor in parallel is the same.
A person absorbs a dose of 1 Gy of alpha radiation. What is the effective dose?
20 Sv effective dose (Sv) = dose (Gy) * QF 1 Gy * 20 rad = 20 Sv
Which Maxwell's law describes the so far un-toppled observation that there are no magnetic monopoles?
2nd
A 6 ohm and a 4 ohm resistor is connected to a 12V battery in parallel. Find the current through the 4 ohm resistor.
3A -- 12V/4 ohm
Which Maxwell's law says that a changing magnetic flux through a loop generates current in the loop?
3rd
What is the approximate radius of Ca (A=40, Z=20)?
4.1*10^(-15) m r = (1.2*10^-15 m)(A^(1/3)) = (1.2*10^-15 m)(40^(1/3))
Special relativity is mostly important for: - bombs - space travel - every day phenomena - high energy phenomena
high energy phenomena
What is used between the anode and cathode of a cathode ray tube to induce a movement of electrons between the plates? - vacuum - high voltage - rarefied gas - glass
high voltage
A positive charge enters a uniform magnetic field as shown. What is the direction of the magnetic force? [velocity pointing east, +q, x field] - to the left - to the right - down - up
up
With a converging lens of focal length f=21.5 cm, a sharp image is formed at 40 cm behind the lens. What is the object distance?
+46.5 cm f = 21.5 cm di = 40 cm 1/f = 1/di + 1/do --> do = [1/f - 1/di]^(-1) = +46.5
In a lens arrangement, a real object has height 6 cm and a real image of height 3 cm. What is the magnification of the lens?
-0.5 m = hi/ho Because a real image is produced, the image is inverted, and thus the height is negative. m = -3cm/6cm = -0.5
An object is placed 12 cm from a convex mirror of focal length f = -8 cm. Find the image distance.
-4.8 cm 1/f = 1/do + 1/di 1/di = 1/f - 1/do = -1/8 - 1/12 = -5/24 di = (-5/24)^-1
A concave lens has a magnification: - 0 < m < 1 - m = 1 - m > 1 - 0 > m > -1 - m < -1
0 < m < 1
Unpolarized light enters a polarizer with vertical polarization axis. The light that passes through passes another polarizer with transmission axis at 40 degrees to the horizontal. What is the intensity of the light after the second polarizer expressed as a fraction of the original intensity?
0.207 transmission axis 40 degrees to the horizontal --> 90-40=50 (angle that relates to the line of the normal) I1 = 0.5 I0 I2 = I1 cos^2 (theta) = 0.5 I0 cos^2 (theta) I2 = 0.5 I0 cos^2 (50) = 0.207 I0
A 60 ohm and a 90 ohm resistor are connected in series across a 30V battery. What is the current flowing across the 60 ohm resistor?
0.2A In series: Re = R1 + R2 = 150 ohms I = V/R = 30V/150 ohms
How much energy is stored in a capacitor if the voltage difference is 900V and the plates hold a charge of q = 1mC = 10^(-3) C?
0.45 J E = 0.5QV = 0.5(10^(-3) C)(900V)
Which of these have the same biological effect? - 1 rad of X-ray and 2 rad of alpha particles - 1 rad of X-ray and 1 rad of protons - 1 rad of beta and 10 rad of alpha particles - 1 rad of alpha particles and 10 rad of protons
1 rad of alpha particles and 10 rad of protons 1 rad alpha = 20 RBE 10 rad protons = 10 * 2 RBE = 20 RBE
How many neutrons does oxygen-18 have?
10 A = 18, Z = 8 A - Z = (protons + neutrons) - protons = 10 neutrons
Which of these is guaranteed to be fatal? - 1000 rem over a short period of time - 1000 rem over a long period of time - 400 rem over a long period of time - 400 rem over a short period of time
1000 rem over a short period of time
The electric potential difference between two oppositely charged plates is ΔV = 9V. How much work does it take to move an electron from the positively charged plate to the negatively charged plate?
14.4x10^(-19) J W = -q(Vb - Va) = -(-1.602x10^(-19) C)(9V) = 1.44*10^(-18) J
For the rear view mirror of the car of question 3, assume that another car is 20 m away from the mirror and appears to be 0.75 its size. What is the absolute value of the image distance? (Since the image is behind the mirror, the actual image distance is negative.)
15 m m = - (di/do) di = -m(do) = -0.75(20 m) = -15 m
A radioactive source has 120 particles decay in a minute. What is its activity?
2 Bq activity = ΔN/Δt = 120 particles/60 sec = 2 Bq
A certain radiation deposits 10 J in 5 kg of absorbing material. What is the absorbed dose?
2 Gy 1 Gy = 1 J / 1 kg 10 J / 5 kg = 2 Gy
A light ray is incident on a plane mirror at a 50 degree angle to the normal of the mirror's surface. At what angle in degrees to the horizontal does the reflected ray leave the mirror?
40 angle of incidence = angle of reflection = 50 given to the normal --> to the horizontal --> 90 - 50 = 40
What is the binding energy per nucleon of helium-4? Hint: helium-4 is A=4, Z=2
7.1 MeV BE = (mass of const.) - (mass of nucleon) = [2(1.007825u) + 2(1.1008665u)] - 4.002602u (BE/A) * 931.5 MeV/u = 7.1 MeV
Assuming the mass of a nucleus is precisely the atomic mass number in atomic mass units (u) and the nucleus is perfectly spherical, what is the density of a nucleus? Hint: your unit will be (u/m^3)
7.24*10^(-45)
Assume that the electron's mass is 9x10^(-31) kg. The speed of light is 3x10^8 m/s. What is the rest energy of a million electrons?
81x10^(-9) Joules rest energy = m0c^2 x 1 million
In the case of the magnetic field charged particles feel a force at what orientation compared to the direction of motion? - parallel - 45 degrees - 90 degrees - 180 degrees
90 degrees
In the case of the magnetic field charged particles feel a force at what orientation compared to the magnetic field? - parallel - 45 degrees - 90 degrees - 180 degrees
90 degrees
The antenna's immediate fields are the magnetic and electric field, which build and collapse at: - 0 degrees - 45 degrees - 90 degrees - 180 degrees
90 degrees
The difference between the sum of the masses of a nucleon and the mass of the nucleon is 0.1 u. What is the binding energy of the nucleus?
93.2 MeV Binding energy = (mass of constituents) - (mass of nucleon) = 0.1 u (931.5 MeV/u) = 93.2 MeV
[?] percent of the atom's mass is contained in its nucleus, which is about [?] in size.
99.9 ; 10^(-15) meters
The wavelength of the transmitted radiation can be related to the antenna which produced it. [T/F]
True
The electron flow of this antenna creates a fluctuating magnetic field. What physical law describes a concentric magnetic field appearing around a current, and which Maxwell's equation does it relate to? - Ampere's law and the 3rd equation - Ampere's law and the 4th equation - Faraday's law and the 3rd equation - Faraday's law and the 4th equation
Ampere's law and the 4th equation
To deduce the formula for the equivalent resistance of a parallel circuit, one combines: - Energy conservation and Ohm's Law - Charge conservation and Ohm's Law - Charge conservation and Coulomb's Law - Energy conservation and Coulomb's Law
Charge conservation and Ohm's Law
To deduce the formula for the equivalent resistance of a series circuit, one combines: - Energy conservation and Ohm's Law - Charge conservation and Ohm's Law - Charge conservation and Coulomb's Law - Energy conservation and Coulomb's Law
Energy conservation and Ohm's Law
Which Thomson shows a diffraction pattern for electrons, proving that it has wave nature? - J.J. (father) - G.P. (son)
G.P.
Two polarizers are set up with transmission axis perpendicular to each other. A third polarizer is inserted between them at 60 degrees to the vertical. What can we say about the light coming through? - Light will pass through with the same intensity as the original beam - Light will pass through, but with less intensity as the original beam - No light will pass through
Light will pass through, but with less intensity as the original beam.
In the ultimate speed experiment, the units used to plot the horizontal axis correspond to the kinetic energy of the electron are: - Joules - Megaelectronvolts - Calories - Kilocalories
Megaelectronvolts (MeV)
Which of these causes the most biological damage? - 10 Sv of alpha radiation - 10 Sv of gamma radiation - 10 Sv of beta radiation - They all cause the same amount of biological damage
They all cause the same amount of biological damage -- 1 Sv of any radiation causes the same amount of biological damage
Which of these is false? - The strong force acts on the constituents of protons and neutrons - The strong force is a long range force - The strong force is not enough to keep the nucleus stable when high numbers of protons repel each other - The strong force is stronger than the Coulomb force
The strong force is a long range force --> short-range, acts when nucleons are less than 10^(-15) m apart
A twin travels in a spaceship at half light speed while his brother stays on Earth. They each measure the speed of light. What can we say about their measurement? - They measure the same speed because they set their watches the same when the one twin left. - They measure the same speed because the speed of light in a vacuum is the same in any inertial frame. - They measure different speeds because they are moving relative to each other. - They measure it to be the same because they are twins.
They measure the same speed because the speed of light in a vacuum is the same in any inertial frame.
Which of these quantities does not influence the capacitance of a capacitor? - The separation distance of the capacitor plates - Area of the capacitor plates - Permittivity of the material between the capacitor plates - Thickness of the capacitor plates
Thickness of the capacitor plates
Curved mirrors can be understood if one imagines having small pieces of flat mirrors placed along the curvature, each obeying the law of reflection. [T/F]
True
To calculate the magnetic field strength at a distance "r" from a straight current carrying wire, a clever choice for the closed loop around the wire has the shape of: - a circle - a line - a rectangle - an equilateral triangle
a circle
What type of mirror is a makeup mirror that magnifies the image of a person's face? - a flat mirror - a concave mirror with object within focal length - a concave mirror with object outside focal length - a convex mirror with object within focal length
a concave mirror with object within focal length
The muon is an elementary particle called: - a Higgs boson - a quark - a gauge boson - a lepton
a lepton
If a lens has a negative focal length and we place an object in front of it outside its focal length, what image do we NOT expect to get? - an upright image - a diminished height image - a real image - a virtual image
a real image
From a point source, energy is radiated in all directions. What is the typical wave form we consider when talking about electromagnetic waves? - a longitudinal wave - a sine wave - a square wave - none of the above
a sine wave
It is our experience that magnetic effects are caused by moving charges. Which of the following will not cause a magnetic effect? - a proton moving in an accelerator - an electron circulating in a closed conductor - a spinning electron - a spinning neutron
a spinning neutron -- a neutron has no charge
What is the energy of a photon of the color red if its frequency is f = 450THz = 450x10^12 Hz = 450x10^12 1/s. Planck's constant is h = 6.626x10^(-34) J*s.
about 30x10^(-20) J Planck's formula for the quantized energy of the massless photon: E = hf
The magnitude of the magnetic field is proportional to the current standing wave's: - amplitude - intensity - wavelength - frequency
amplitude
Sinks and sources can be described as divergence is mathematical language and can represent various physical situations. According to our current knowledge of electricity and magnetism, which field will be more likely described by a single source or divergence when thought of as a vector field? - an electric field - a magnetic field
an electric field
To start to produce radiation by a simple dipole antenna, what is to be established first according to your study of the antenna video? - a changing current - a changing magnetic field - an electron flow - a magnetic field
an electron flow
Where should an object be placed in front of a concave mirror such that it produces an image at the same location as the object? - at the focal point of the mirror - at half the focal point of the mirror - at the radius of curvature - cannot be determined
at the radius of curvature di = do = d d = 2f f = 1/2 d = 1/2 r d = r
The twin in the spaceship traveling at half speed of light sends regular light pulses as it is moving away from Earth. His brother receives these signals at time intervals: - at half the intervals the ship brother sees - at the same as the intervals the ship brother sees - at twice the intervals the ship brother sees - at four times the intervals the ship brother sees
at twice the intervals the ship brother sees -- because he is moving away from Earth, the intervals are twice as long. If he were moving towards Earth, the intervals would be half as long.
A rectangular closed path is used for the calculation of Ampere's Law for a solenoid as shown. Along which segment of this path is the magnetic field zero due to that segment being perpendicular to the field lines?
because the field lines are horizontal, the perpendicular lines will cross the field lines at a 90 degree angle (bc)
As a massive object approaches the speed of light, its mass: - becomes larger and larger - becomes smaller and smaller - stays the same
becomes larger and larger -- As an object increases in speed, so does the amount of energy that it has, this energy is what we refer to as 'the increase in mass' (inertial mass). As an object approaches the speed of light, its mass becomes infinite and it is unable to go any faster than light travels
In the experiment investigating ultimate speed, an electro is: - being accelerated - being decelerated - at rest
being accelerated
When using Kirchhoff's rules, the direction of the loop is chosen: - clockwise - counterclockwise - clockwise or counterclockwise at will
clockwise or counterclockwise at will
When the electron flow is at maximum at the end with no momentary flow, the magnetic field: - collapses - becomes maximum
collapses
When two waves meet in phase at a screen, they produce [?] interference. When they meet out of phase, they produce [?] interference.
constructive; destructive
If a rear view mirror of a car produces an image that is upright but smaller than the object, what kind of mirror is being used? Think in terms of what kind of mirror can produce an image that is upright but smaller. - concave - convex - flat
convex -- for a convex mirror, the image is always virtual, upright, and smaller.
If a real image is to be produced, what kind of lens can be used and what will the sign be of the focal length? - concave lens, positive focal length - concave lens, negative focal length - convex lens, positive focal length - convex lens, negative focal length
convex lents, positive focal length
A wire carries a current in the upward vertical direction. Which way will the magnetic field circle around the wire? - clockwise - counterclockwise
counterclockwise -- RHR with the thumb pointing up and fingers curling in counterclockwise direction
The net amount of charge that passes through the wire's full cross section per unit time is called: - electric potential - resistance - current - capacitance
current
Kirchhoff's junction rule is related to the: - current and energy conservation - voltage and energy conservation - current and charge conservation - voltage and charge conservation
current and charge conservation
Potential energy per unit is called: - electric potential - resistance - current - capacitance
electric potential
Charlie is watching a waiter come and go as the Orient express zooms by him at his train station. Charlie is a comoving observer. [T/F]
false -- comoving observers are at rest relative to the frame (observer is moving with its reference frame)
By rubbing two objects together with different affinity for electrons, we can create charges. [T/F]
false -- you cannot create or destroy charges; electric charge is conserved
A current carrying wire loop in a magnetic field will experience two forces in the same direction on two opposing sides from its middle axis. The forces will balance and the frame will not rotate. This statement is: - true in any case - true only if the loop is in a certain position - false; the forces will be in the same direction, but the loop will rotate - false; the forces will be in opposite directions and the loop will rotate
false; the forces will be in opposite directions and the loop will rotate
As a massive object approaches the speed of light, its kinetic energy: - gets larger and larger - gets smaller and smaller - stays the same
gets larger and larger -- hella speed = hella KE
The general theory of relativity presents a new theory of: - electricity - magnetism - gravity - everything
gravity
A dipole is an antenna which accommodates: - half a wavelength - a full wavelength - double the wavelength - any wavelength
half a wavelength
Which of these nuclei is the least stable? - helium-3 - helium-4 - oxygen-16 - uranium-238
helium-3
To measure the voltage across a circuit element, the voltmeter should be connected: - in parallel - in series
in parallel
Changing polarity of the voltage in the antenna produces an electric field: - perpendicular - out of phase - in phase - parallel
in phase
Unpolarized light has the electric field vectors of its electromagnetic wave pointing: - in a single direction - along the propagation direction - in random directions - in two perpendicular directions
in random directions
~~EXAM 1 MATERIAL~~ Special relativity concerns itself with [?] reference frames where Newton's law of [?] holds.
inertial ; inertia
Electrons are shot at a screen one-by-one through two slits. What appears on the screen is an [?] pattern.
interference
Which nucleus is the most stable? - helium-4 - carbon-12 - tin-120 - iron-56
iron-56
A lightbulb is connected to a battery. A second identical light bulb is now added to the circuit in a series arrangement. How is the brightness of the bulb affected compared to the original brightness of the bulb? - it depends on the resistance of the bulb - it is brighter - it is the same - it is dimmer
it is dimmer
If we increase the current to twice the value in question #9 to 0.6 A over the same battery, how will the resistance change? - it will reduce to half as much - it will reduce to one quarter as much - it will stay the same - it will increase to twice as much
it will reduce to half as much R = V/I = 1.5V / 0.6A = 2.5 ohms
What happens to a charged particle in an electric or magnetic field that allows us to observe and learn about it? - nothing observable - it glows - it makes a sound - its path is deflected
its path is deflected
According to the relativity principle, the [?] must be the same in all [?] inertial reference frames.
laws of physics ; all
The muons from cosmic rays reach the earth as they travel through the atmosphere because their lifetime from the point of view of the earth observer is: - undetectable - shorter - longer - absolute
longer -- a muon's mean lifetime is 2.2x10^(-6) s, and because the fraction of v can never be or exceed 1 due to the natural speed limit, the relativistic particle from the POV of the earth observer will be longer than in the muon's rest frame.
What words did Captain Nemo not use to describe electricity? - effortless - powerful - magical - swift
magical
What is the correct description of the image of the makeup mirror of the previous question? - magnified, inverted, real, in front of the mirror - magnified, upright, virtual, behind the mirror - magnified, upright, virtual, in front of the mirror - magnified, upright, real, behind the mirror
magnified, upright, virtual, behind the mirror
When the electron flow reverses and there is a flow in the antenna, the magnetic field reaches its: - minimum - maximum
maximum
If you watch two identical clocks, one moving relative to you and one at rest relative to you, you observe the moving clock to tick [?]
more slowly.
Which phenomenon was not observed in ancient times that stems from electricity? - muscle contraction of a frog leg - rubbed amber - electric ray - lightning - St. Elmo's fire - electric spark
muscle contraction of a frog leg
~~EXAM 2 MATERIAL~~ The magnetic field direction relative to the magnetic field lines shown when iron filings are scattered around a magnet are: - parallel to the field lines - perpendicular to the field lines - determined by other factors - none of the above
parallel to the field lines -- the direction of the magnetic field is tangent to a field line.
A vacuum also has permittivity described by a universal constant: ε0 = 8.85x10^(-12) C^2/(Nm)^2. It is called the [?] of free space. - resistance - capacitance - permittivity - permeability
permittivity
The electric and magnetic field oscillate perpendicular to each other in electromagnetic radiation, which propagates in a direction: - perpendicular only to the E field - perpendicular only to the B (H) field - perpendicular to the E field and the B (H) field
perpendicular to the E field and the B (H) field
To understand diffraction, one must consider every point of a wave front as a [?].
point source -- Huygens' Principle
If the image of the rear view mirror of the previous question is upright and smaller, what is the sign and magnitude range of the magnification? - positive; greater than 1 - positive; less than 1 - negative; greater than -1 - negative; less than -1
positive; less than 1 upright = positive smaller = less than 1
The antenna is designed to: - receive electromagnetic waves - transmit electromagnetic waves - receive and transmit electromagnetic waves - neither receive or transmit electric nor magnetic waves
receive and transmit electromagnetic waves
The ratio of the voltage "V" and the current "I" gives the: - electric potential - resistance - current - capacitance
resistance
To limit radiation in any one place outside the tumor but to keep the beam passing through the tumor the whole time, what technique is used? - rotating the beam around the patient - using several weaker beams at once - turning the patient - concentrating the radiation from a well-chosen direction
rotating the beam around the patient (and using narrow beams)
Curl or circulation in a fluid can be seen by what motion of a twig in the fluid? - oscillation - rotation - straight line motion - no motion
rotation
A traveler is moving compared to an earth-bound observer in a spaceship. He uses light bouncing between the two mirrors as a light clock. The perpendicular distance the light travels from one mirror to another, the distance the spaceship travels at its speed and the distance the earth-bound observer measures for the light in the clock form a right triangle. What mathematical tool do we use to find the time dilation formula in this geometry? - equilateral triangles - the Pythagorean theorem for right triangles - trigonometry for right triangles - isosceles triangles
the Pythagorean theorem for right triangles
The magnetic field strength is proportional to: - the direction of the magnet - the size of a magnet - the magnetic field lines - the magnetic field lines per surface area
the magnetic field lines per surface area
When the magnetic field vector is PERPENDICULAR to the velocity of a charged particle, what can we say about the magnetic force and the parallelogram used to calculate it? - The magnetic force is maximum and the parallelogram is a rectangle. - the magnetic force is half the maximum and the parallelogram is a rectangle. - the magnetic force is at minimum and the parallelogram is a rectangle. - the magnetic force is at minimum and the parallelogram closes to zero area.
the magnetic force is maximum and the parallelogram is a rectangle.
When the magnetic field vector is PARALLEL to the velocity of a charged particle, what can we say about the magnetic force and the parallelogram used to calculate it? - the magnetic force is zero and the parallelogram closes to zero area. - the magnetic force is maximum and the parallelogram is a rectangle. - the magnetic force is zero but the parallelogram has a nonzero area. - nothing special can be said about the force and the area.
the magnetic force is zero and the parallelogram closes to zero area.
Which of these is guaranteed to cause cancer? - 1000 rem over a long period of time - 400 rem over a short period of time - 400 rem over a long period of time - the occurrence of cancer is probabilistic
the occurrence of cancer is probabilistic
A rectangular closed path is used for the calculation of Ampere's Law for a solenoid as shown. Along which segment of this path is the magnetic field zero due to that segment being outside the solenoid?
the path parallel to the field lines that are not within the solenoid (ab)
A rectangular closed path is used for the calculation of Ampere's Law for a solenoid as shown. Along which segment of this path is the magnetic field parallel to the segment?
the path parallel to the field lines that run within the solenoid (cd)
When calculating the force due to a magnetic field that is at an angle to the velocity of a moving charge, which projection of the magnetic field vector relative to the velocity vector determines the magnitude of the magnetic force? - the parallel projection - the perpendicular projection
the perpendicular projection
A light clock is placed in a spaceship with a space traveler. From the traveler's point of view who moves along with the clock, it measures: - the earth time - a longer than the proper time - the proper time - a shorter than the proper time
the proper time
What is true of two atoms with the same atomic number but different atomic mass numbers? - they are different elements with the same amount of neutrons - they are different isotopes of the same element - they are different elements with the same mass
they are different isotopes of the same element
The absolute value of the strength of the magnetic force on a moving charge does not depend of which of the following quantities? - the magnitude of charge - the angle between the magnetic field and velocity vector - the magnitude of velocity of a charge moving in a magnetic field - the sign of the charge
the sign of the charge -- the sign affects only which way the path bends, but won't affect the magnitude of the force
The electron flow produces a maximum on one side of the antenna, reverses, produces a maximum on the other side of the antenna, and reverses again. What do we call the characteristic physical quantity that describes this oscillation? - the signal amplitude - the signal frequency - the signal length - the signal strength
the signal frequency
In determining the magnetic force on a charged particle moving in a magnetic field, we can use a geometric representation to calculate the magnitude of this force. This involves the area of a parallelogram marked out by what two physical vector quantities? - the velocity and the magnetic field - the velocity and the electric field - the magnetic field and the electric field - two projections of the magnetic field
the velocity and the magnetic field
Why are tumors treated with X-rays and gamma radiation? - they are the most powerful radiation - they have the lowest biological effect - they cause less heat - they are the least penetrating radiation
they have the lowest biological effect (the same dose will do less harm)
How does Hewitt describe the observation Einstein made about time in his video? - time is eternal - time is distorted - time is stretched - time is absolute
time is stretched
What is the key goal of radiation safety? - to avoid radiation entirely - to limit absorbed radiation as much as possible - to use radiation for safety
to limit absorbed radiation as much as possible
Why did Benjamin Franklin do the dangerous experiment of flying a kite into a storm? - to prove that static electricity and lightning were the same - to harvest energy from lightning - to impress his friends - to study lightning safety
to prove that static electricity and lightning were the same
A positive charge enters a uniform magnetic field as shown. What is the direction of the magnetic force? [velocity pointing north, +q, x field] - to the left - to the right - down - up
to the left
The actual graph of an electron accelerated to high speeds is not a linearly increasing straight line, but rather a curved graph that levels off at the value of the speed of light. [T/F]
true -- the point of this experiment is to show how the speed of something as small as the electron cannot be increased to more than the speed of light. Hence, light has the ultimate velocity.
~~ EXAM 3 ~~ A plane mirror has a [?] image that appears behind the mirror without actual light rays going through it.
virtual
Kirchhoff's loop rule is related to the: - current and energy conservation - voltage and energy conservation - current and charge conservation - voltage and charge conservation
voltage and energy conservation
Can light propagate without a medium?
yes