Problems for Test 1 Flashcards
The Starship Enterprise approaches the planet Risa at a speed of 0.8c relative to the planet. On the way, it overtakes the intergalactic freighter Astra. The relative speed of the two ships as measured by the navigator on the Enterprise is 0.5c. At what speed is Astra approaching the planet.
A 0.5 kg bomb is sliding along an icy pond (frictionless surface) with velocity of 2.0 m/s to the west. The bomb explodes into two pieces. After the explosion, a 0.2 kg piece moves south at 4.0 m/s. What are the components of the velocity of the 0.3 kg piece?
p=mv
A 0.015 kg marble moving to the right at 0.4 m/s has a head-on elastic collision with a 0.045 kg marble sitting at rest on a smooth, level surface. Which of the following are the correct magnitudes and directions of the velocities of the two marbles after the collision?
The position of a Hydrogen atom is known to within a certain range, what is the uncertainty in momentum?
The position of an object with a mass and velocity is known within a certain range. What is the fractional uncertainty of the momentum?
A photon has a collision with a stationary electron and loses 5% of its energy, and is scattered at 180 degrees. What is the wavelength of the incident photon?
Photon of what minimum frequency are required to remove electrons from gold? The work function for gold is 4.8 eV.
The de Broglie wavelength of the matter wave associated with an electron accelerated by a voltage of 50 V is about,
Ba137 emits a gamma ray photon of 0.66 MeV during an isomeric transition. Calculate the recoil energy.
A meter stick is observed to be only 0.9 m long to an inertial observer. At what speed, relative to the observer, must the meter stick be moving?
the temperature of a lead brick with given mass is increased by given temperature. The specific heat is given. What is the increase in mass of the brick?
What is the energy of the photon whose momentum is equal to that of a 5 MeV electron?
calculate ratio of v/c and m/m0 for electron and proton
Two electrons are initially at rest, separated by 0.1 nm. After the electrons are released, they repel each other. What is the kinetic energy of each electron when they are 1 nm apart?
What is the kinetic energy of an electron whose velocity is 90% of the speed of light?
Assume an uncertainty in the momentum of an electron is equal to one-half of its momentum. Calculate the uncertainty in position of a 1 MeV electron.
What is the wavelength of …
What is the closest distance that a 4.0 MeV alpha particle can make a gold nucleus?
Calculate the uncertainty in position of an electron that was accelerated across a potential difference 10^5 +- 100V
A meson decays in a given time. The kinetic energy is equal to the rest energy. What distance does it travel when observed from earth?
Two particles with the same mass m are emitted in the same direction with momenta 10mc and 20mc respectively. As seen from the slower one what is the velocity of the faster particle and vice versa?
A particle is in the ground state of an infinite square well potential. Find the probability of finding the particle
How much energy is required to accelerate an electron from rest to a speed of 0.9c?
How fast must a particle move before its kinetic energy equals its rest energy?
Two particles are aimed directly at each other. The first particle is moving at a speed of 0.8c to the right and the second particle is moving to the left at a speed of 0.7c. Assume both speeds are measured relative to the laboratory frame.
Normalize the wave equation
A small object of mass 1.50 mg is confined to move between two rigid walls separated by 1.00 cm.
What is the mean value of the number of counts?
What is its standard deviation (S.D.)?
What is the theoretical minimum S.D. of the mean?
A solution of 131I containing an activity of 10^7 gamma/s is spilled on an approximately circular area of 1 m in diameter. Determine the fluence rate 10 m above the center of the contaminated area.
MeV, J, erg
Electrons have been removed from a beryllium atom (Z=4) until only one remains. Determine the energy of the photon that can be emitted, if the remaining electron is in the n=2 level.
Which one of the following will result in an electron transition from the n=4 level to n=7 level in a hydrogen atom?
A bullet of mass 40 gm travels to 1000 m/s. What wavelength can we associate with it?
The wavelength of the first line of the Lyman series of a ten time ionized Na atom (Z=11) is
The total number of electron states with n=2,l=1 for Hydrogen atom is
A hydrogen-like ion has the wavelength difference between the first lines of the Balmer and Lyman series equal to 16.58 nm. What ion is it?
Observer A measures the relativistic velocity of a rocket as v and a comet as u. Here u and v are parallel and in the direction of observer’s positive x-axis. The speed of the comet as measured by an observer on the rocket is:
A mass of a particle is m. In order for its total energy to be twice its rest energy, its momentum must be
The work function for a particular metal is 4.0 eV . Which one of the following best describes the wavelength of electromagnetic radiation needed to eject electrons from the metal?
A particle of rest mass m moves with a speed 0.6c. Its kinetic energy is
How much energy will be released if 1.0 g of material were completely converted into energy
A laser emits pulse of light with energy 5*10^3 J Determine the number of photons in the pulse if the wavelength of the light is 480 nm
What is the de Broglie wavelength of an electron ( m = 9.11*10^−31 kg ) in a 5.0*10^3 V x-ray tube?
A 2 MeV photon is scattered by a Compton interaction. What is the maximum energy transferred to the recoiled electron?
What is the angular momentum of the electron in the n = 5 state of the Hydrogen?
Calculate the ionization potential of Li2+
Calculate the radius of the n = 2 electron orbit in the Bohr hydrogen atom.
Calculate the orbital radius for the n = 2 state of Li2+
What are the energies of the photons with the two longest wavelengths in the Paschen series?
How many energy levels of the He+ ion lie below −1 eV ?
Calculate the current of the electron in the ground state of the hydrogen atom.
Calculate the reduced mass of the He+ system
What is the reduced mass of a system of two particles of equal mass, such as an electron and positron, orbiting about their center of mass?
Calculate the de Broglie wavelength of a 245 keV electron.
How much energy is required to remove an electron from the n = 5 state of He+?
What is the momentum of a photon of lowest energy in the Balmer series of hydrogen?
How many electrons per second strike the target in an X-ray tube operating at current of 50 mA.
if the potential difference between the anode and cathode is 100 kV , how much power is expended?
How much force acts on the electron in the ground state of the hydrogen atom?
The length of an uniform radioactive rod is L. Derive an expression for the fluence at a point P. The shortest distance to from the middle of the rod to P is x and assume the rate of emission of gamma is N/s.
The diagram shows a circular radioactive disc source with emission rate SA gamma/s and radius R. Derive an expression for the fluence at the point P.
A point source emits beta particles at a rate of 10^7 gamma/s. What is the fluence density at a distance of 30 cm from the source?
A solution of 131I containing an activity of 10^7 gamma/s is spilled on an approximately circular area of 1 m in diameter. Determine the fluence rate 1 m above the center of the contaminated area.
A point source of 60Co gamma rays emits equal numbers of photons of 1.17 and 1.33MeV , giving a flux density of 3.7*10^9 photons.cm^−2.sec^−1 at a specified location. What is the energy flux density there, expressed in erg.cm^−2.s^−1 and in J.m^−2.min^−1?
The classical electron radius is of the order of
The wavelength of the K(alpha) line in iron (Z=26) is known to be 193 pm. Then what would the wavelength of the K(alpha) line for copper (Z=29)?
A proton and an electron have the same kinetic energy and are moving at speeds much less than the speed of light. The ratio of De Broglie wave length of the electron to that of the proton is:
How many electron states are possible in a Hydrogen atom if its energy is -3.4 eV?
A photon in light beam A has twice the energy of a photon in light beam B. The ratio P_A/P_B of their momenta is:
The absorption coefficient of aluminum is 0.73 1/cm for xrays of wavelength 0.20 A and the density of aluminum is 2.1 g/cm^3. The mass absorption coefficient is:
How many electrons per second strike the target in an X-ray tube operating at a current of 50 mA?
The intensity of a light beam with a wavelength of 500 nm is 2000 W.m^-2. The photon fluence ( in number. m^-1s^-1) is about
A source of 2 MeV gamma rays produces a uniform fluence of 106 cm-2 at a distance of 150 cm. What is the energy fluence at that point?
Compute the cut off bremsstrahlung wavelength for an electron moving under the influence of a potential of 40 keV.
