test questions from all of our previous physics tests and their corresponding answers.
unlike poles repel each other
which of the following situations is NOT true for magnets?
the magnitude is greatest close to the poles
where is the magnitude of the magnetic field around a permanent magnet the greatest?
all of the above (the number of field lines that cross a certain area, ABcosθ, surface area x magnetic field component normal to the plane of surface)
one useful way to model magnetic field strength is to define a quantity called magnetic flux. which of the following definitions of magnetic flux is correct?
magnetic field lines appear to end at the northpole of a magnet
all of the following statements about magnetic field lines around a permanent magnet are true except which one?
which compass needle orientation in the figure might correctly describe the magnet's field at that point?
a microscopic magnetic region composed of a group of atoms whose magnetic fields are aligned in a common direction is called a _. in mose materials when these groups are randomly distributed, the substance will show _ magnetism.
line up mainly in one direction
in a magnetized substance, the domains...
domain alignment persists after the external magnetic field is removed
in a permanent magnet...
the orientation of domains fluctuates
in soft magnetic materials such as iron, what happens when an external magnetic field is removed?
What term is used to describe a perfect radiator and absorber of electromagnetic radiation?
the ultraviolet catastrophe
Classical electomagnetict theory predicted that the energy radiated by a blackbody would become infinite as the wavelength became shorter. What was the contradiction between observation and this result called?
What were the units of light energy emitted by blackbody radion origianlly called?
3.00 x 10^14 Hz
What is the frequency of a photon with an energy of 1.99x10^-19 J?
A monochromatic light beam with a quantum energy value of 3.00eV is incident upon a photocell. The work function of the photo cell is 1.6 eV. What is the maximum kinetic energy of the ejected electrons?
According to the Rutherford model, what makes up most of the volume of an atom?
What is the concentration of positive charge and the mass in Rutherford's atomic model called?
When a high potential difference is applied to a low pressure gas, what kind of spectrum will the gas emit?
The wavelengths of the spectrum are characteristics of the element emitting the light.
Which of the following statements is true about emission spectra?
Photons are emitted when electons jump froma higher energy to a lower energy state.
What causes the bright lines in the emission spectum of an element to occur?
the scattering of alpha particles
What observation confirmed de Broglie's theory of matter waves?
the more accurately one value is measued, the less accurately the other value is known
According to the Heisenberg uncertainty principle, which of the following statements about the simultaneous measurements of position and momentum is true?
The electron may be found at various distances from the nucleus.
Why is a probability wave required to describe an electron's location?
protons and nuetrons
The nucleus of an atom is made up of which of the following combinations of particles?
the number of protons in the nucleus
To which of the the following is the atomic number of a given element equivalent?
the number of protons and nuetrons present
What does the mass number of a nucleus indicate?
If there are 128 nuetrons in Pb-210, how many nuetrons are found in the nucleus of Pb-206?
the energy released when the nucleons bind together to form a stable nucleus
What is the binding energy of a nucleus?
As the number of proton in the nucleus increases, the repulsive force....
Of the main types of radiation emitted from naturally radioactive isotopes, which is the most penetrating?
atomic number decreases by two
The alpha emission process results in the daughter nucleus differing in what manner from the parent?
atomic number changes by one
Thee beta emission process results in the daughter nucleus differing in what manner from the parent?
In the radioactive formula 220/86 Rn ----> 216/84Po + X what does X represent?
How many half-lives does it take for a radioactive substance to decay to 12.5 perceent of its original amount?
140/56Ba , 93/36Kr
What daughter isotopes are produced when a neutron combines with a nucleus of 235/92 U? Assume that three nuetrons are also produced in the reaction.
At this time, all nuclear reactors operate through.....
Which interaction of nature binds nuetrons and protons into nuclei?
Which interaction of nature depends on the distance through which it acts and is involved in beta decay?
Which interaction of nature holds the planets, stars, and galexies together, even though its effect on elementary particles is negligible?
Which interaction of nature binds atoms and molecules by attracting unlike charges and repulsing like charges?
the angle between true north and north indicated by a compass
which statement describes earths magnetic declination?
the geographic south pole of earth and earths magnetic north pole are relatively close to each other
which of the following statements about earths magnetic field is true?
decreasing the current and reducing the number of coils
which of the following modifications to a solenoid would be most likely to decrease the strength of its magnetic field?
the magnetic field, B
according to the right hand rule, if a current carrying wire is grasped in the right hand with the thumb in the direction of the current the four fingers will curl in the direction of...
form concentric circles around the wire
the lines of the magnetic field around a current carrying wire...
all of the above (when the particle is stationary, when the particle is moving parallel to the magnetic field, when the particle is not charged)
under which of the following conditions is thenet magnetic force on a charged particle equal to zero?
an electron that moves with a speed of 3.0x10^4 m/s perpendicular to a uniform magnetic field of 0.40 T experiences a force of what magnitude? (qe = 1.60x10^-19C)
perpendicular to both the current and the magnetic field
the direction of the force on a current carrying wire in an external magnetic field is ...
what is the path of an electron moving perpendicular to a magnetic field?
the two wires will attract eachother
consider two long straight parallel wires, each carrying a current I. if the currents move in the same direction...
high temperature field
a current can be induced in a closed circuit without the use of a battery or an electrical power supply by moving the circuit through a...
both magnitude and direction
a loop of wire is rotated 360 degrees across an external magnetic field. during one period of revolution the induced current changes in...
a coil with 150 turns and a cross sectional area of 1m^2 experiences a magnetic field whose strength increases by +0.65T in 1.80s. the plane of the coil is perpendicular to the plane of the applied magnetic field. what is the emf in the coil?
a generators maximum output is 220V. what is the rms potential difference? (round up)
a current carrying wire 0.50m long is positioned perpendicular to a uniform magnetic field. if the current is 10.0 A and there is a resultant force of 3.0 N on the wire due to the interaction of the current and field, what is the magnetic field strength?
the rms current in an ac current is 3.6 A. find the maximum current.
a transformer has 15 turns in its primaryand 6750 turns in its secondary. if the potential difference across the primary is 1.2 V, what is the potential difference across the secondary?
in the oscillating electric and magnetic fields
where is energy stored in electromagnetic waves?
where the crest from one wave overlaps the trough from another
two beams of coherent light are shining on the same sheet of white paper. when referring to the crests and troughs of such waves, where will the darkness appear on the paper?
for stable interference to occur the phase difference must be
the distance between two slits in a double slit interference experiment is 2.9x10^-6m. the first order bright fringe is measured on a screen at an angle of 12 degrees from the central maximum. what is the wavelength of the light?
monochromatic light shines on the surface of a diffraction grating with 5.3x10^3 lines/cm. the first order maximum is observed at an angle of 17 degrees. find the wavelength.
they remain in phase
if light waves are coherent...
which of the following is a device that produces an intense, nearly parallel beam of coherent light?
all of the above (to treat glaucoma, to measure distance, to read bar codes)
a laser can be used to...
both monochromatic and coherent
the diagram below represents a group of light waves emitted simultaneously from a single source. these light waves would be classified as...
which diagram best represents the phenomenon of diffraction
which pattern of bright and dark bands could have been produced by a beam of monochromatic light passing through a single narrow slit?
monochromatic light passes through a single narrow slit, forming a diffraction pattern on a screen. which graph best represents the light intensity of the single slit diffraction pattern for monochromatic light?