Physics Final Quiz Review
The direction of the magnetic force on the proton ccw is
out of the screen
The bar magnet is pushed toward the center of a wire loop. looking from above, which is true?
there is a clockwise current induced in the wire
A rigid container holds oxygen gas (O2) at 100ºC. The average velocity of the molecules is
0
The magnetic field is confined to the region inside the dashed lines; it is zero outside. The metal loop is being pulled out of the magnetic field. Which is true?
There is a clockwise induced current in the loop.
Electromagnetic waves are ______ waves which need ______ to propagate.
Transverse, no medium.
A long, straight wire extends into and out of the screen (the red side of the compass is north, pointing in the direction of the B field). The current in the wire is
out of the screen
The electric field is always _____ to an equipotential surface
perpendicular
Metal spheres 1 and 2 are connected by a metal wire. What quantities do spheres 1 and 2 have in common?
same potential
A large charged bee of mass .05kg and charge +1mC is placed in a uniform vertical electric field as shown. What must the magnitude of the electric field be to keep the bee suspended just above the surface of the earth?
500 N/C
Three possible processes A, B, and C take a gas from state i to state f. For which process is the magnitude of the work the largest?
Process A, straight up
to calculate carnot heat engine efficiency:
1-waste/input
At the midpoint between two equal charges:
E=0 V>0
The electron drift speed in a typical current-carrying wire is:
Extremely slow (≈ 10^-4 m/s).
The SI unit for absolute temperature is
Kelvin
A Heat Engine can never be more than 100% efficient because of
The first law of thermodynamics (conservation of energy)
Heat is the
energy that moves between a hotter object to a colder object
A and B are identical lightbulbs connected to a battery as shown. Which is brighter?
in series, same brightness
How to calculate efficiency of heat engine?
n = work/input or 1-waste/input
A metal bar moves through a magnetic field. The induced charges on the bar is shown in:
pos(left) and neg(Right) charge on ends
Gauss's law is useful for calculating electric fields that are:
symmetric
Two positive charges are equal. Which has more electric potential energy?
the charge with greater distance
Spherical Gaussian surfaces of equal radius R surround two spheres of equal charge Q. Which Gaussian surface has the larger electric field?
they have the same electric field; equal R
If V(x) = 2x^2 - 3x, what is the electric field at x=2?
-5
The second law of thermodynamics says that
-The entropy of an isolated system never decreases. -Heat never flows spontaneously from cold to hot.
What process is shown on a pv diagram \
a: isochoric b: isobaric c: isothermal d: none of the above <----
For an electro-magnetic wave with the electric field initially up and the magnetic field initially out of the page, which direction is the wave propagating?
right
Which spherical Gaussian surface has the larger electric flux?
the larger one
Two protons, A and B, are in an electric field. Which proton has the larger acceleration?
the one in narrower flow
If a bar magnet is cut in half, you end up with
two magnets with two poles each with one south facing other's north
A point charge q is located distance r from the center of a neutral metal sphere. The electric field at the center of the sphere is:
0
A weather balloon is loosely inflated with helium at a pressure of 1 atm and a temperature of 27 °C. The volume of the helium is 6.0 m^3. When the balloon rises to 8000 m the temperature has dropped to -73 °C and the pressure has dropped to 0.5 atm. What is the new volume of the helium in the balloon??
8m^3; ideal gas law PV=nRT so P1V1/T1=P2V2/T2
What is the name of an ideal-gas process in which no heat is transferred?
Adiabatic
Metal spheres 1 and 2 are touching. Both are initially neutral. i) The positively charged rod is brought near 1. ii) The spheres are separated. iii) The charged rod is then removed. Afterward, the charges on the spheres are:
Q1 - Q2 +
If the inductor in an LC circuit is increased, the frequency of the natural oscillations is?
decreased
The magnetic field shown is decreasing. Which figure shows the induced electric field?
counter clockwise
When R2 is added to R1 in parallel how does the current from the battery change (increase or decrease)? _______
increase
A flask of warm gas and a flask of cold gas are brought together and allowed to mix. After the mixing the entropy has:
increased
A large -20ºC ice cube is dropped into a super-insulated container holding a small amount of 5ºC water, then the container is sealed. Ten minutes later, is it possible that the temperature of the ice cube will be colder than -20ºC?
no
The metal loop is being pulled through a uniform magnetic field. Is the magnetic flux through the loop changing?
no
A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements must be true for this case?
no work is done
Two rocks have equal mass. Which has more gravitational potential energy?
the higher rock
Two protons, one after the other, are launched from point 1 with the same speed. They follow the two trajectories shown. The protons' speeds at points 2 and 3 are related by
they are =
An electron follows the trajectory shown from i to f. At point f, relative to the initial speed vi, the final speed vf is:
vf<vi
If you heat a substance in an insulated container, is it possible that the temperature of the substance remains unchanged?
yes
The equivalent capacitance for two capacitors in parallel is:
add them
A rod attracts a positively charged hanging ball. The charge on the rod is:
either negative or neutral
The pos charged ball shown below is suspended from a large, uniformly charged positive plate. It swings with period T. If the ball is discharged, will the period increase, decrease, or stay the same?
increase
The metal loop is rotating in a uniform magnetic field. Is the magnetic flux through the loop changing?
yes
Three points inside a parallel-plate capacitor are marked. Which is true?
E1=E2=E3
For a Carnot engine operating off the temperature difference between the deep ocean (-3˚C) and the ocean surface (27 ˚C) the maximum efficiency is:
10%; convert to K and use efficiency=1-cold/hot
A 60 watt light bulb left on for 1000 hours uses $___ of electricity if the cost is $0.20/kWhr.
12$
A certain wire has a resistance R. What is the resistance (in terms of R) of a second wire made of the same material, that is half as long and half the diameter?
2R
A 2 coulomb positively charged particle starts at rest at the left plate of a pair of parallel plates as shown. If the potential difference between the 2 plates is 4 Volts, and the mass of the particle is 4Kg, the speed of the particle when it reaches the second plate is?
2m/s
An ideal (Carnot) engine has an efficiency of 25%. It is being operated between 2 constant temperature reservoirs with a hot temperature reservoir of 400K. What is the temperature of the cold reservoir?
300K; efficiency= 1-cold/hot
