GRE Physics Exam 2
GRE PHYSICS EXAM 2 NEWEST 2025/2026 COMPLETE ALL 100
QUESTIONS AND CORRECT DETAILED ANSWERS |ALREADY
GRADED A+||ALREADY GRADED A+
Which of the following functions could represent the radial wave function for an
electron in an atom? (r is the distance of the electron from the nucleus; A and b
are constants.)
I. A e- b r
II. A sin(br)
III. A/r
(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III
Choice (A) gives the common form of the wave function for radial wave functions
of an electron in an atom as from quantum mechanics. Choice (A).
Positronium is an atom formed by an electron
and a positron (antielectron). It is similar to the hydrogen atom, with the positron
replacing the proton. If a positronium atom makes a transition from the state with
n = 3 to a state with n = 1, the energy of the photon emitted in this transition is
closest to
(A) 6.0 eV
(B) 6.8 eV
(C) 12.2 eV
(D) 13.6 eV
(E) 24.2 eV
Positronium has a base ground energy of 6.8 eV and the transition gives us: 6.8
eV(1/(1^2) - 1/(3^2)) = 6.8 eV(1 - 1/9) = 6.0 eV. Choice (A).
1|Page
, GRE Physics Exam 2
If the total energy of a particle of mass m is
equal to twice its rest energy, then the magnitude
of the particle's relativistic momentum is
(A) mc/2
(B) mc / 2
(C) mc
(D) 3mc
(E) 2mc
Pythagorean Question: sqrt(2^2 - 1^2) = sqrt(4 - 1) = sqrt(3). So we have
sqrt(3)*mc. Choice (D).
If a charged pion that decays in 10-8 second in
its own rest frame is to travel 30 meters in the
laboratory before decaying, the pion's speed must
be most nearly
(A) 0.43 ¥ 108 m/s
(B) 2.84 ¥ 108 m/s
(C) 2.90 ¥ 108 m/s
(D) 2.98 ¥ 108 m/s
(E) 3.00 ¥ 108 m/s
This is pretty damn close to the speed of light just by inspection and 2.98E8 m/s
should fit the details and we have choice (D).
In an inertial reference frame S, two events occur on the x-axis separated in time
by Dt and in space by Dx. In another inertial reference frame
S¢, moving in the x-direction relative to S, the two events could occur at the same
time under which, if any, of the following conditions?
(A) For any values of Dx and Dt
2|Page
, GRE Physics Exam 2
(B) Only if ΩDx /DtΩ< c
(C) Only if ΩDx /DtΩ> c
(D) Only if ΩDx /DtΩ= c
(E) Under no condition
Timelike events occur when the light acts as x/t = c. Choice (D).
If the absolute temperature of a blackbody is increased by a factor of 3, the
energy radiated per second per unit area does which of the following?
(A) Decreases by a factor of 81.
(B) Decreases by a factor of 9.
(C) Increases by a factor of 9.
(D) Increases by a factor of 27.
(E) Increases by a factor of 81.
Wien's Law gives us, the 3^4 = 81 as the factor of energy radiated per second per
unit area due to the temperature tripling. Choice (E).
Consider the quasi-static adiabatic expansion
of an ideal gas from an initial state i to a final
state f. Which of the following statements is
NOT true?
(A) No heat flows into or out of the gas.
(B) The entropy of state i equals the entropy
of state f.
(C) The change of internal energy of the gas is - z PdV.
(D) The mechanical work done by the gas is
PdV z .
(E) The temperature of the gas remains constant.
During a quasi-"static" expansion, we should expect the temperature of the gas to
remain constant throughout its expansion. Choice (E).
3|Page
, GRE Physics Exam 2
A constant amount of an ideal gas undergoes the
cyclic process ABCA in the PV diagram shown
above. The path BC is isothermal. The work
done by the gas during one complete cycle,
beginning and ending at A, is most nearly
(A) 600 kJ
(B) 300 kJ
(C) 0
(D) -300 kJ
(E) -600 kJ
The work done by the gas during this process is 300 kJ (1/2 300 kJ 2 m^3) = 300 kJ
by the area of the approximated triangle. Choice (B).
An AC circuit consists of the elements shown
above, with R = 10,000 ohms, L = 25 millihenries, and C an adjustable capacitance.
The AC voltage
generator supplies a signal with an amplitude of 40 volts and angular frequency of
1,000 radians per second. For what value of C is the amplitude of the current
maximized?
(A) 4 nF
(B) 40 nF
(C) 4 mF
(D) 40 mF
(E) 400 mF
w = sqrt^-1(LC) ==> C = (w^2)L = (1000^2)(2.5E-2) = 2.5e4
Which two of the following circuits are high-pass
filters?
4|Page
GRE PHYSICS EXAM 2 NEWEST 2025/2026 COMPLETE ALL 100
QUESTIONS AND CORRECT DETAILED ANSWERS |ALREADY
GRADED A+||ALREADY GRADED A+
Which of the following functions could represent the radial wave function for an
electron in an atom? (r is the distance of the electron from the nucleus; A and b
are constants.)
I. A e- b r
II. A sin(br)
III. A/r
(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III
Choice (A) gives the common form of the wave function for radial wave functions
of an electron in an atom as from quantum mechanics. Choice (A).
Positronium is an atom formed by an electron
and a positron (antielectron). It is similar to the hydrogen atom, with the positron
replacing the proton. If a positronium atom makes a transition from the state with
n = 3 to a state with n = 1, the energy of the photon emitted in this transition is
closest to
(A) 6.0 eV
(B) 6.8 eV
(C) 12.2 eV
(D) 13.6 eV
(E) 24.2 eV
Positronium has a base ground energy of 6.8 eV and the transition gives us: 6.8
eV(1/(1^2) - 1/(3^2)) = 6.8 eV(1 - 1/9) = 6.0 eV. Choice (A).
1|Page
, GRE Physics Exam 2
If the total energy of a particle of mass m is
equal to twice its rest energy, then the magnitude
of the particle's relativistic momentum is
(A) mc/2
(B) mc / 2
(C) mc
(D) 3mc
(E) 2mc
Pythagorean Question: sqrt(2^2 - 1^2) = sqrt(4 - 1) = sqrt(3). So we have
sqrt(3)*mc. Choice (D).
If a charged pion that decays in 10-8 second in
its own rest frame is to travel 30 meters in the
laboratory before decaying, the pion's speed must
be most nearly
(A) 0.43 ¥ 108 m/s
(B) 2.84 ¥ 108 m/s
(C) 2.90 ¥ 108 m/s
(D) 2.98 ¥ 108 m/s
(E) 3.00 ¥ 108 m/s
This is pretty damn close to the speed of light just by inspection and 2.98E8 m/s
should fit the details and we have choice (D).
In an inertial reference frame S, two events occur on the x-axis separated in time
by Dt and in space by Dx. In another inertial reference frame
S¢, moving in the x-direction relative to S, the two events could occur at the same
time under which, if any, of the following conditions?
(A) For any values of Dx and Dt
2|Page
, GRE Physics Exam 2
(B) Only if ΩDx /DtΩ< c
(C) Only if ΩDx /DtΩ> c
(D) Only if ΩDx /DtΩ= c
(E) Under no condition
Timelike events occur when the light acts as x/t = c. Choice (D).
If the absolute temperature of a blackbody is increased by a factor of 3, the
energy radiated per second per unit area does which of the following?
(A) Decreases by a factor of 81.
(B) Decreases by a factor of 9.
(C) Increases by a factor of 9.
(D) Increases by a factor of 27.
(E) Increases by a factor of 81.
Wien's Law gives us, the 3^4 = 81 as the factor of energy radiated per second per
unit area due to the temperature tripling. Choice (E).
Consider the quasi-static adiabatic expansion
of an ideal gas from an initial state i to a final
state f. Which of the following statements is
NOT true?
(A) No heat flows into or out of the gas.
(B) The entropy of state i equals the entropy
of state f.
(C) The change of internal energy of the gas is - z PdV.
(D) The mechanical work done by the gas is
PdV z .
(E) The temperature of the gas remains constant.
During a quasi-"static" expansion, we should expect the temperature of the gas to
remain constant throughout its expansion. Choice (E).
3|Page
, GRE Physics Exam 2
A constant amount of an ideal gas undergoes the
cyclic process ABCA in the PV diagram shown
above. The path BC is isothermal. The work
done by the gas during one complete cycle,
beginning and ending at A, is most nearly
(A) 600 kJ
(B) 300 kJ
(C) 0
(D) -300 kJ
(E) -600 kJ
The work done by the gas during this process is 300 kJ (1/2 300 kJ 2 m^3) = 300 kJ
by the area of the approximated triangle. Choice (B).
An AC circuit consists of the elements shown
above, with R = 10,000 ohms, L = 25 millihenries, and C an adjustable capacitance.
The AC voltage
generator supplies a signal with an amplitude of 40 volts and angular frequency of
1,000 radians per second. For what value of C is the amplitude of the current
maximized?
(A) 4 nF
(B) 40 nF
(C) 4 mF
(D) 40 mF
(E) 400 mF
w = sqrt^-1(LC) ==> C = (w^2)L = (1000^2)(2.5E-2) = 2.5e4
Which two of the following circuits are high-pass
filters?
4|Page
