The Solution for GRE Physics Practice Test [41-60]
추천글 : 【GRE】 Solution for GRE Physics Practice Test
41. A 3p electron is found in the 3P3/2 energy level of a hydrogen atom. Which of the following is true about the electron in this state?
⑴ answer: A
⑵ 선택규칙(selection rule) : 전자 전이의 제한
① 주양자수 변화량 : Δn은 음수일 수도 있음
② 각양자수 변화량 : Δℓ = ±1
○ 예 : 1s → 2p는 허용되지만 1s → 2s는 허용되지 않음
③ 자기 양자수 변화량 : Δmℓ = 0, ±1
④ 스핀 양자수 변화량 : 전자는 전이할 때 스핀이 바뀌지 않음 (스핀 보존의 법칙)
⑤ 일반적으로 Δj = 0, ±1 : j = 0 → j = 0이 금지되며, 특수한 경우 Δj = ±2인 경우도 있음
🄑 P → P는 Δℓ = 0이므로 허용되지 않음
🄒 P 오비탈이므로 ℓ = 1
🄓 스핀 양자수 s는 ±1/2만 가능함
🄔 다전자 원자에서 각양자수 또한 전자의 에너지 준위에 영향을 줌
42. Light of wavelength 500 nanometers is incident on sodium, with work function 2.28 electron volts. What is the maximum kinetic energy of the ejected photoelectrons?
⑴ answer: B
⑵ 광전효과 : K = hf - Φ = hc / λ - Φ = 0.202 (eV)
43. The line integral of u = yi - xj + zk around a circle of radius R in the xy-plane with center at the origin is equal to
⑴ answer: C
⑵ 스토크스 정리(stokes theorem)
44. A particle of unit mass undergoes one-dimensional motion such that its velocity varies according to v(x) = βx-n, where β and n are constants and x is the position of the particle. What is the acceleration of the particle as a function of x?
⑴ answer: A
⑵ 계산 과정
45. The circuits below consist of two-element combinations of capacitors, diodes, and resistors. Vin represents an ac-voltage with variable frequency. It is desired to build a circuit for which Vout ≈ Vin at high frequencies and Vout ≈ 0 at low frequencies. Which of the following circuits will perform this task?
⑴ answer: E
⑵ 고역통과필터(high-pass filter)
46. A circular wire loop of radius R rotates with an angular speed ω in a uniform magnetic field B, as shown in the figure below. If the emf ℇ induced in the loop is ℇ0 sin ωt, then the angular speed of the loop is
⑴ answer: C
⑵ 맥스웰 제4법칙
47. A wire is being wound around a rotating wooden cylinder of radius R. One end of the wire is connected to the axis of the cylinder, as shown in the figure below. The cylinder is placed in a uniform magnetic field of magnitude B parallel to its axis and rotates at N revolutions per second. What is the potential difference between the open ends of the wire?
⑴ answer: C
⑵ 나무랑 붙어 있는 도선도 같이 회전
⑶ 처음에 도선의 한쪽 끝은 축 중심에 연결되어 있고, 다른 열린 끝은 원통 표면에 있음
⑷ 계산 과정 : 맥스웰 제4법칙
48. The half-life of a π+ meson at rest is 2.5 × 10-8 second. A beam of π+ mesons is generated at a point 15 meters from a detector. Only 1/2 of the π+ mesons live to reach the detector. The speed of the π+ mesons is
⑴ answer: C
⑵ 시간 지연 : 2.5 × 10-8 × (1 - (v/c)2)-1/2 = (15 / v) ⇔ v = 2c / √5
49. The infinite xy-plane is a nonconducting surface, with surface charge density σ, as measured by an observer at rest on the surface. A second observer moves with velocity vx̂ relative to the surface, at height h above it. Which of the following expressions gives the electric field measured by this second observer?
⑴ answer: C
⑵ 길이수축으로 2차 관찰자에게는 면적이 γ배 감소하고, 전하밀도가 γ배 증가하는 것처럼 관측됨
⑶ 따라서 정지계에서 무한평면 전기장 σ / 2ϵ0이 2차 관찰자에게는 γσ / 2ϵ0으로 관찰됨
50. In inertial frame S, two events occur at the same instant in time and 3c · minutes apart in space. In inertial frame S', the same events occur at 5c · minutes apart. What is the time interval between the events in S'?
⑴ answer: C
⑵ 로렌츠 스칼라 시공거리 : (cΔt)2 - (Δx)2 = -9c2 = (cΔt')2 - (Δx')2 ⇔ Δt' = 4 min
51. The solution to the Schrödinger equation for a particle bound in a one-dimensional, infinitely deep potential well, indexed by quantum number n, indicates that in the middle of the well the probability density vanishes for
⑴ answer: B
⑵ 상자 속 입자
52. Three
⑴ answer: C
⑵
53. A d
⑴ answer: C
⑵
54. When th
⑴ answer: B
⑵
55. The
⑴ answer: A
⑵
56. A lump o
⑴ answer: C
⑵
57. An a
⑴ answer: C
⑵
58. Wh
⑴ answer: E
⑵
59. Whi
⑴ answer: B
⑵
60. If a singly io
⑴ answer: B
⑵
입력: 2026.05.09 11:16
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