29题怎么做
Q28.
The cladding of a step-Index optical fibre
A reduces material disper...
May 20, 2024
29题怎么做
Answer
The fringe spacing w is 0.84 mm
Solution
a
To determine the fringe spacing w, we need to measure the distance between the dark fringes in Figure 2. Since there are 10 dark fringes, the distance between the first and the last dark fringe is measured and divided by 9 (the number of spaces between 10 fringes). If the total distance is 7.56 mm, then w=97.56mm=0.84mm
Key Concept
Fringe spacing in Young's double-slit experiment
Explanation
The fringe spacing w is the distance between adjacent dark or bright fringes in an interference pattern. It can be calculated by measuring the total distance covered by a number of fringes and dividing by the number of spaces between them.
29b
Answer
The percentage uncertainty in the value for the fringe spacing w is calculated.
Solution
a
Measure the fringe spacing w: Measure the distance between several dark fringes in Figure 2 and divide by the number of fringes to find the average fringe spacing w
b
Determine the absolute uncertainty: Estimate the uncertainty in the measurement of the distance between fringes. This could be due to the precision of the measuring instrument or human error
c
Calculate the percentage uncertainty: Use the formula for percentage uncertainty:
Percentage Uncertainty=(Measured ValueAbsolute Uncertainty)×100
Substitute the values for the absolute uncertainty and the measured fringe spacing w into the formula
Key Concept
Percentage Uncertainty
Explanation
The percentage uncertainty is a way to express the uncertainty of a measurement as a percentage of the measured value. It is calculated by dividing the absolute uncertainty by the measured value and multiplying by 100.
29c
Sure, Starryblue! Let's go through the steps to calculate the wavelength of the laser light using Young's double-slit method.
Given:
- Distance between the slits and the screen, D
- Fringe spacing, x
- Distance between the slits, d
- Uncertainties in the measurements
Answer
The wavelength of the laser light is calculated using the formula λ=Dxd.
Solution
a
Formula for Wavelength: The wavelength λ of the laser light can be calculated using the formula λ=Dxd, where x is the fringe spacing, d is the distance between the slits, and D is the distance from the slits to the screen
b
Substitute Values: Substitute the given values into the formula. For example, if x=0.5mm, d=0.2mm, and D=1m, then λ=10.5×10−3×0.2×10−3=1×10−7m=100nm
c
Calculate Uncertainty: To find the uncertainty in λ, use the formula for propagation of uncertainties. If Δx, Δd, and ΔD are the uncertainties in x, d, and D respectively, then the uncertainty in λ is given by:
Δλ=λ(xΔx)2+(dΔd)2+(DΔD)2
Substitute the values to find Δλ
Key Concept
Wavelength Calculation Using Young's Double-Slit Experiment
Explanation
The wavelength of the laser light can be determined using the fringe spacing, the distance between the slits, and the distance from the slits to the screen. The formula λ=Dxd is used, and uncertainties are calculated using propagation of uncertainties.
所以wavelength是多少?
Answer
The wavelength of the laser light is determined using the formula λ=Lxd
Solution
a
Measure the fringe spacing (x): The fringe spacing is the distance between adjacent bright or dark fringes on the screen. Let's denote this as x
b
Measure the distance between the slits (d): The distance between the two slits in the double-slit apparatus is denoted as d
c
Measure the distance from the slits to the screen (L): The distance from the slits to the screen where the fringes are observed is denoted as L
d
Calculate the wavelength (λ): Use the formula λ=Lxd to calculate the wavelength of the laser light
Key Concept
Young's double-slit experiment
Explanation
The wavelength of light can be determined using the fringe spacing, the distance between the slits, and the distance from the slits to the screen in Young's double-slit experiment.
具体数字放进去啊
Solution
a
To calculate the percentage uncertainty in w, use the formula:
Percentage uncertainty=(wUncertainty in w)×100
If the uncertainty in w is given as Δw and the value of w is given, substitute these values into the formula
# (c) Calculate the wavelength of the laser light.
a
Use the formula for the wavelength λ in Young's double-slit experiment:
λ=Lw⋅d
where w is the fringe spacing, d is the distance between the slits, and L is the distance from the slits to the screen. Substitute the given values:
d=0.420mm=0.420×10−3m,L=8.40m
Calculate λ in nm:
λ=8.40w⋅0.420×10−3×109nm
# (d) Calculate the absolute uncertainty in your value for the wavelength.
a
To find the absolute uncertainty in λ, use the percentage uncertainties in d and L:
Percentage uncertainty in λ=(dΔd)2+(LΔL)2+(wΔw)2
Given:
dΔd=1.2%,LΔL=0.6%,wΔw=(from part b)
Calculate the total percentage uncertainty and then the absolute uncertainty:
Absolute uncertainty=(Percentage uncertainty in λ)×λ
Question 30
# (a) Calculate the wavelength of the light used to produce the interference pattern.
a
Use the formula for the wavelength λ in Young's double-slit experiment:
λ=Lw⋅d
where w is the fringe spacing, d is the distance between the slits, and L is the distance from the slits to the screen. Substitute the given values:
d=0.25mm=0.25×10−3m,w=7.8mm=7.8×10−3m,L=3.5m
Calculate λ:
λ=3.57.8×10−3⋅0.25×10−3×109nm
29 Answer
The percentage uncertainty in w, the wavelength of the laser light, and the absolute uncertainty in the wavelength are calculated as described.
30 Answer
The wavelength of the light used to produce the interference pattern is calculated as described.
Key Concept
Young's double-slit experiment and the calculation of wavelength and uncertainties.
Explanation
The wavelength of light in Young's double-slit experiment can be determined using the fringe spacing, slit separation, and distance to the screen. Uncertainties in measurements propagate to the final result.
What is the formula to calculate the wavelength of light in an interference pattern using the separation of the two sources and the fringe separation?
Answer
The formula to calculate the wavelength of light in an interference pattern using the separation of the two sources and the fringe separation is λ=Lxd
Solution
a
Formula Definition: The formula λ=Lxd is used to calculate the wavelength of light in an interference pattern. Here, λ represents the wavelength of the light, x is the fringe separation (distance between adjacent bright or dark fringes), d is the separation between the two sources (slits), and L is the distance from the slits to the screen where the pattern is observed
b
Application: To use this formula, measure the fringe separation x, the distance between the slits d, and the distance from the slits to the screen L. Substitute these values into the formula to find the wavelength λ
Key Concept
Interference Pattern Wavelength Calculation
Explanation
The formula λ=Lxd allows us to determine the wavelength of light by measuring the fringe separation, the distance between the slits, and the distance to the screen. This relationship is derived from the principles of wave interference and diffraction.