Textbook Question
INT A beam of electrons is incident upon a gas of hydrogen atoms. What minimum speed must the electrons have to cause the emission of 656 nm light from the 3→2 transition of hydrogen?
9
views
35. Special Relativity
Inertial Reference Frames
7:05 minutesProblem 31d
Textbook Question
FIGURE P39.31 shows the wave function of a particle confined between x = 0 nm and x = 1.0 nm. The wave function is zero outside this region. Calculate the probability of finding the particle in the interval 0 nm ≤ x ≤ 0.25 nm.
Verified step by step guidance1
Step 1: Understand the problem. The wave function ψ(x) represents the probability amplitude of a particle confined between x = 0 nm and x = 1.0 nm. The probability of finding the particle in a specific interval is calculated using the integral of the square of the wave function over that interval.
Step 2: Analyze the graph. The wave function ψ(x) is a triangular function that starts at ψ(0) = 0, increases linearly to a maximum value of c at x = 0.5 nm, and then decreases linearly back to ψ(1) = 0. The function is zero outside the region 0 ≤ x ≤ 1 nm.
Step 3: Write the expression for the probability. The probability of finding the particle in the interval 0 nm ≤ x ≤ 0.25 nm is given by: P = ∫[0 to 0.25] |ψ(x)|² dx. Since ψ(x) is linear in this region, its equation can be determined using the slope-intercept form of a line.
Step 4: Determine the equation of ψ(x) for 0 ≤ x ≤ 0.5 nm. The slope of the line is m = c / 0.5 = 2c. Thus, ψ(x) = 2cx for 0 ≤ x ≤ 0.5 nm. Substitute this into the probability expression: P = ∫[0 to 0.25] (2cx)² dx.
Step 5: Simplify the integral. Expand (2cx)² to get 4c²x². The integral becomes P = ∫[0 to 0.25] 4c²x² dx. Solve this integral by applying the power rule for integration: ∫x² dx = (x³ / 3). After integrating, evaluate the result at the limits x = 0 and x = 0.25.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
7mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Wave Function
The wave function, denoted as ψ(x), describes the quantum state of a particle in a given region. It contains all the information about the particle's position and momentum. The square of the wave function's absolute value, |ψ(x)|², gives the probability density of finding the particle at a specific position within the defined boundaries.
Recommended video:
Guided course
08:30
Intro to Wave Functions
Probability Density
Probability density is a measure derived from the wave function that indicates the likelihood of finding a particle in a particular region of space. For a one-dimensional case, it is calculated as |ψ(x)|². To find the probability of locating the particle within a specific interval, one must integrate the probability density over that interval.
Recommended video:
Guided course
8:13Intro to Density
Normalization of the Wave Function
Normalization ensures that the total probability of finding the particle within the entire space is equal to one. This is achieved by integrating the probability density over the entire range of the wave function and setting the result equal to one. A properly normalized wave function is essential for accurate probability calculations in quantum mechanics.
Recommended video:
Guided course
08:30Intro to Wave Functions
14:1mWatch next
Master Inertial Reference Frames with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice