## GRE Physics GR 1777, Problem 011 Solution

GRE Physics GR 1777 Problem Solution 011. Quantum Mechanics (Characteristic X-rays) Solution By definition in Wikipedia, characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is “characteristic” to each element. Answer (C) References https://en.wikipedia.org/wiki/Characteristic_X-ray http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/xrayc.html

## GRE Physics GR 1777, Problem 010 Solution

GRE Physics GR 1777 Problem Solution 10. Quantum Mechanics (Photoelectric effect) Solution The maximum kinetic energy of the emitted electrons is , where is the maximum kinetic energy of the emitted electrons from the metal surface, is the frequency of light, and is the work function of the metal. Also, if we want to stop…

## GRE Physics GR 1777, Problem 009 Solution

GRE Physics GR 1777 Problem Solution 009. Classical Mechanics (Kinematics) Solution , where is the root-mean-square speed of molecules in an ideal gas, is the mass of the molecule, and is the temperature of the system. Since , then . Therefore, . Answer (D)

## GRE Physics GR 1777, Problem 008 Solution

GRE Physics GR 1777 Problem Solution 008. Thermodynamics (Laws of thermodynamics) You should know about First law of thermodynamics where is the amount of heat, is the internal energy, is the pressure, and is the volume of the system. Solution If we want to make a process that the increase in the internal energy is…

## GRE Physics GR 1777, Problem 007 Solution

GRE Physics GR 1777 Problem Solution 007. Thermodynamics (Thermodynamic Processes) Solution A reversible process in thermodynamics is a process that has a constant entropy. Answer (C) The entropy of the system and its environment remains unchanged. References https://en.wikipedia.org/wiki/Reversible_process_(thermodynamics)

## GRE Physics GR 1777, Problem 005 Solution

GRE Physics GR 1777 Problem Solution 005. Electrodynamics (Maxwell’s Equations) Solution In Maxwell’s equations, Ampère’s law (with Maxwell’s correction) is . We can write this equation as , where is the current (the electric displacement current). is change of electric fields with respect to the time (rate of change of the electric flux). If we…

## GRE Physics GR 1777, Problem 004 Solution

GRE Physics GR 1777 Problem Solution 004. Electrodynamics Solution Net resistance in a parallel circuit is Then, total resistance in circuit is . By the Ohm’s law, , the total current is , . In a parallel circuit, the current is divided. The ratio of the individual current is the inverse ratio as individual resistance,…

## GRE Physics GR 1777, Problem 003 Solution

GRE Physics GR 1777 Problem Solution 003. Classical Mechanics (Oscillations) Solution Angular frequency : Period : In the simple harmonic pendulum, where L is the length of the pendulum. Using above equations, , then we can see that . Since , , Then , therefore . Answer (E)

## GRE Physics GR 1777, Problem 002 Solution

GRE Physics GR 1777 Problem Solution 002. Classical Mechanics (Momentum and Energy) Solution By the linear momentum conservation, 1) x-direction : 2) y-direction : Therefore, Also, using work-energy theorem, If we assume that all energy generated by collision is converted to heat, then the heat energy produced by the collision is Answer (E)

## GRE Physics GR 1777, Problem 001 Solution

GRE Physics GR 1777 Problem Solution 001. Classical Mechanics (Force) Solution The force is Since and , . Answer (E)