一九八三年CUSPEA试题(三)(英文)

Solve 5 of the following 6 problems.C1. An 'air conditioner'is a device used to cool the inside of a home. It is, in essence, a refrigeratorin which mechanical work is done and heat is removed from the (cooler) inside and rejected tothe (warmer) outside.A home air conditioner operating on a reversible carnot cycle between the inside absolute temperature T2 and the outside absolute temperature T1>T2 consumes P Joules/sec from the powerlines when operating continuously.a) In one second, the …     

1984年CUSPEA试题(二)(英文)

B1. Consider a hydrogen atom, and assume that the proton, instead of being a point, is auniformly charged sphere of radius R <相似文献   

1987年CUSPEA试题(二)(英文)

B1. A monochromatic beam of cold neutrons enters from the left in the experiment shown schematicallybelow. The beam passes through a polarizer, P, which transmits only neutrons whose magnetic mo-ment μ is parallel to their velocity v. (Those with μ antiparallel to v are completely rejected .)The polarized beam then passes adiabatically into and out of a region of length L in which there isa uniform magnetic field B0 oriented perpendicular to the neutron path.a) Give the normalized spin wav…     

1986年CUSPEA试题(二)(英文)

B1. Using the uncertainty principle, in any of its various forms, estimate the quantity in question in each partof this problem. Do not be concerned with factors of order unity. (D not solve exactly.)a ) The ground state energy of a hydrogen-like ion, assuming the Hamiltonian to beb ) The ground state energy of a hydrogen-like ion, assuming thatwhere u=mc2. Is your result valid for all Z? What is the connection between the result just obtainedand that obtained in part a)?c ) The penetration…     

1982年CUSPEA试题(二)(英文)

MODERN PHYSICS(4 hours)Solve 5 of the following 6 problemsB1Our universe is filled with black body radiation (photons) at a temperature T≈3.K. This isthought to be a relic of early developments following the "big bang".(i) Express the photon number density n analytically in terms of T and universal constants. Youranswer should explicitly show the dependence on T and on universal constants. However, a certainnumerical cofactor may be left in the form of a dimensionless integral which n…     

一九八三年CUSPEA试题(一) (英文)

CLASSICAL PHYSICS(4 Hours)Solve 6 of the following 7 problems.A railroad flatcar at mass M can roll without friction along a straight horizontal track as shown. N men, each of mass m are initiallystanding on the car which is at rest.a) The N men run to one end of the car in unison so that their speed relative to the car is Vr justbefore they jump off (all at the same time). Calculate the velocity of the car after the men havejumped off.b) The N men run off the car, one after the other…     

1981年CUSPEA试题(三)(英文)

GENERAL PHYSICS (4 hours)资料Solve 5 of the following 7 problems.1. Describe Millikan's experiment to measurethe electric charge of the electron.Show schematically the apparatus neededand describe the crucial parts. What arethe equations that govern the experiment?2. a) A spherical object rotates with an angular frequency . If the only forcepreventing centrifugal disintegrationof the object is gravity. what is theminimum density the object musthave? Use this to estimate the minimumdensi…     

1986年CUSPEA 试题(一)(英文)

PART ACLASSICAL PHYSICS(4 hours )Do 5 of the 6 problemsA1 A sphere of radius R and of relative permeability μ is placed in a region of time-independent initiallyuniform magnetic flux-density B0 in the z-direction. The dielectric constant is unity through…     

1982年CUSPEA试题(三)(英文)

GENERAL PHYSICS (4 hours)Solve 6 of the following & problemsC1A classical gas of N point particles, all of mass m, occupies a volome V and is in thermodynamic equilibrium at temperature T. The particles interact with each other pairwise, via the “hardsphere”, potential where r i j is the distance between particles i and j. Let n = the number dan sity and k the Boltzmann constant. Let p be the pressure and Cv the specific heat (per particle) atconstant volume.Compute Cv and ti.[e sec…     

1981年CUSPEA试题(一)(英文)

MODERN PHYSICS(4 hours)Solve 5 of the following 7 problems.1. Two spin 1/2 particles form a composite system. Spin A is in the eigenstate S'z = + 1/2 andspin B in the eigenstate S'x = + 1/2. What is the probability that a measurement of the total spinwill give the value zero?2. Consider the process of compton scattering. A photon of wavelength λ is scattered off a freeelectron initially at rest. Let λ' be the wavelength of the photon scattered in a direction θ.a) Compute λ' in term…     

1987年CUSPEA试题(三)(英文)

C1. a) What causes the tides on the Earth, for instance the twice-daily high tides seen at the ocean shore?b) The Sun has a much larger mass than the Moon, and yet the tides generated by the Sun are only abouthalf as large as the tides generated by the Moon. Why is this?c) Tides can also be observed in the atmosphere. Barometric pressure in the tropics tends to show a regularperiodic variation of small amplitude (- 1 /103). The atmospheric tide caused by the Moon shows a periodof about 12 …     

1987年CUSPEA 试题(一)(英文)

PART ACLASSICAL PHYSICS(4 hours )Do any 5 of the 6 problemsAl. Consider the motion of a uniform rod of length L and mass m whoseends are constrained to move on a vertical circle of radius R. Assume that there is no friction between the rod and this circular track, butdo not ignore gravity.Find the frequency of small oscillations about the equilibrium position..A2. A hollow cylinder of mass m, subject to gravity g, rolls withoutsipping down the inclined surface of a triangular wedge o…     

1984年CUSPEA试题(三)(英文)

Solve 5 of the following 6 problems.C1. (a ) Consider the emission or absorption of visible light by the molecules of a hotgas. Derive an expression for the frequency distribution F(v) expected for aspectral line of central frequency v0 due to the Doppler broadening. Assume an ideal gas at temperature T with molecular weight M.Consider a vessel filled with argon gas at a. pressure of 10 Torr (1 Torr=l mm of mercury) and a temperature of 2000℃. Inside the vessel is a smallpiece of sodium w…     

1986年CUSPEA试题(三)(英文)

C1. The cross section for the reaction A+B→C+D is δ(v), where v is the relative velocity of A and B andv=|v|.a) A beam of particles of type A, with a density nA particles per. cubic centimeter and velocity v, isincident on NB particles of type B. at rest. Without proof, give the number of reactions A+B→C+Dper second which occur.b) Without proof, give the Maxwell-Boltzmann velocity distribution f(U)dU for point particles of mass mat a temperature T to within a normalization constant …     

1981年CUSPEA试题(2)(英文)

A. MechanicsSolve Problem A3 and either A1 or A2A1. A man wishes to break a longrod by hitting it on a rock. Theend of the rod which is in hisband rotates without displacement.The man wishes to avoid havinga large force act on his hand atthe time the rod hits the rock,which point of the rod should hitthe rock? (ignore gravity)A2. A projectile of mass m is shot(at a velocity v) at a target ofmass M, with a hole containinga spring (with constant k). Thetarget is initially at rest, andcan sli…