Physical constants (speed of light, Planck) in SciPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the speed of light constant from scipy.constants.

SciPy

from scipy.constants import [1]
print(speed_of_light)

Drag options to blanks, or click blank then click option'

Ac

Bplanck

Ch

Dspeed_of_light

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'c' instead of 'speed_of_light' causes a NameError.

Confusing Planck constant names with speed of light.

The speed of light constant is named speed_of_light in scipy.constants.

2fill in blank

medium

Complete the code to print the value of Planck's constant from scipy.constants.

SciPy

from scipy.constants import [1]
print(planck)

Drag options to blanks, or click blank then click option'

Aspeed_of_light

Bhbar

Cplanck

Dc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'hbar' instead of 'planck' imports the reduced Planck constant.

Using 'c' or 'speed_of_light' imports the wrong constant.

The Planck constant is named planck in scipy.constants.

3fill in blank

hard

Fix the error in the code to correctly import and print the reduced Planck constant.

SciPy

from scipy.constants import [1]
print(hbar)

Drag options to blanks, or click blank then click option'

Ahbar

Bspeed_of_light

Cc

Dplanck

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'planck' instead of 'hbar' causes a NameError.

Using 'speed_of_light' or 'c' imports unrelated constants.

The reduced Planck constant is named hbar in scipy.constants.

4fill in blank

hard

Fill both blanks to create a dictionary with keys 'c' and 'h' for speed of light and Planck constant values.

SciPy

from scipy.constants import speed_of_light, planck
constants = {'c': [1], 'h': [2]
print(constants)

Drag options to blanks, or click blank then click option'

Aspeed_of_light

Bplanck

Chbar

Dc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'c' or 'h' as values instead of the imported constants.

Mixing up speed_of_light and planck in the dictionary.

Use the imported names speed_of_light and planck to assign values.

5fill in blank

hard

Fill all three blanks to create a dictionary with keys 'c', 'h', and 'hbar' for speed of light, Planck constant, and reduced Planck constant.

SciPy

from scipy.constants import speed_of_light, planck, hbar
constants = {'c': [1], 'h': [2], 'hbar': [3]
print(constants)

Drag options to blanks, or click blank then click option'

Aplanck

Bspeed_of_light

Chbar

Dc

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the values for 'c' and 'h'.

Using string keys as values instead of constants.

Assign the correct imported constants to each key in the dictionary.

Practice

1. What is the value of the speed of light constant c in scipy.constants measured in?

easy

A. Meters per second

B. Kilometers per hour

C. Miles per second

D. Feet per second

Solution

1. Step 1: Understand the unit of speed of light in scipy.constants

   The speed of light c in scipy.constants is given in meters per second (m/s), which is the standard SI unit for speed.

2. Step 2: Confirm the unit from official documentation or usage

   Checking the official scipy documentation confirms c is in meters per second.

3. Final Answer:

   Meters per second -> Option A

4. Quick Check:

   Speed of light unit = meters per second [OK]

Hint: Speed of light is always in meters per second [OK]

Common Mistakes:

• Confusing meters per second with kilometers per hour
• Assuming miles or feet units
• Not checking scipy documentation

2. Which of the following is the correct way to import and access Planck's constant from scipy.constants?

easy

A. import scipy.constants; scipy.constants.planck

B. import scipy.constants as sc; sc.Planck

C. from scipy.constants import Planck

D. from scipy.constants import planck

Solution

1. Step 1: Recall the exact attribute name for Planck's constant

   In scipy.constants, Planck's constant is accessed as planck (all lowercase).

2. Step 2: Check import syntax correctness

   import scipy.constants; scipy.constants.planck uses import scipy.constants and accesses scipy.constants.planck, which is correct. from scipy.constants import planck tries to import planck directly, which is valid but not the exact syntax shown here. import scipy.constants as sc; sc.Planck uses incorrect capitalization Planck. from scipy.constants import Planck also uses wrong capitalization and import style.

3. Final Answer:

   import scipy.constants; scipy.constants.planck -> Option A

4. Quick Check:

   Correct attribute name is planck, accessed via scipy.constants [OK]

Hint: Planck constant is lowercase 'planck' in scipy.constants [OK]

Common Mistakes:

• Using uppercase 'Planck' instead of lowercase
• Incorrect import syntax
• Trying to import planck directly without correct syntax

3. What is the output of this code snippet?

from scipy.constants import c, planck
wavelength = 500e-9  # 500 nm in meters
energy = planck * c / wavelength
print(round(energy, 20))

medium

A. 3.972891714285714e-16

B. 3.972891714285714e-25

C. 3.972891714285714e-22

D. 3.972891714285714e-19

Solution

1. Step 1: Calculate photon energy using formula E = h * c / wavelength

   Given wavelength = 500 nm = 500e-9 m, Planck's constant (h) and speed of light (c) are constants from scipy.constants. Calculate energy = planck * c / wavelength.

2. Step 2: Perform calculation and round result

   Using scipy.constants values: planck ≈ 6.62607015e-34, c ≈ 299792458, energy ≈ (6.62607015e-34 * 299792458) / 500e-9 = 3.972891714285714e-19 J. Rounded to 20 decimals matches 3.972891714285714e-19.

3. Final Answer:

   3.972891714285714e-19 -> Option D

4. Quick Check:

   Energy = h*c/wavelength = 3.97e-19 J [OK]

Hint: Use E = h*c/wavelength formula with correct units [OK]

Common Mistakes:

• Forgetting to convert nm to meters
• Mixing up multiplication and division
• Rounding too early or incorrectly

4. Identify the error in this code snippet that tries to calculate photon energy:

from scipy.constants import Planck, c
wavelength = 600e-9
energy = Planck * c / wavelength
print(energy)

medium

A. Missing import for speed of light

B. Wavelength should be in nanometers, not meters

C. Planck constant is incorrectly capitalized

D. Division operator should be multiplication

Solution

1. Step 1: Check import statement for Planck constant

   The code imports Planck with uppercase 'P', but in scipy.constants it is lowercase planck. This causes an AttributeError.

2. Step 2: Verify other parts of the code

   Wavelength is correctly converted to meters (600e-9), speed of light c is imported correctly, and the formula uses correct division. So no other errors.

3. Final Answer:

   Planck constant is incorrectly capitalized -> Option C

4. Quick Check:

   Correct attribute is 'planck' lowercase [OK]

Hint: Check exact case for constants in scipy.constants [OK]

Common Mistakes:

• Using uppercase 'Planck' instead of lowercase
• Confusing units of wavelength
• Wrong operator in formula

5. You want to calculate the energy of a photon with wavelength 400 nm using scipy.constants. Which code snippet correctly computes and prints the energy in electronvolts (eV)?

hard

A. from scipy.constants import c, planck
wavelength = 400e-9
energy_ev = planck * c / wavelength
print(round(energy_ev, 3))

B. from scipy.constants import c, planck, electron_volt
wavelength = 400e-9
energy_joule = planck * c / wavelength
energy_ev = energy_joule / electron_volt
print(round(energy_ev, 3))

C. from scipy.constants import c, planck, electron_volt
wavelength = 400
energy_joule = planck * c / wavelength
energy_ev = energy_joule * electron_volt
print(round(energy_ev, 3))

D. from scipy.constants import c, planck
wavelength = 400e-9
energy_joule = planck * c * wavelength
print(round(energy_joule, 3))

Solution

1. Step 1: Calculate photon energy in joules using E = h*c / wavelength

   Use wavelength in meters (400e-9). Calculate energy_joule = planck * c / wavelength.

2. Step 2: Convert energy from joules to electronvolts

   Divide energy_joule by electron_volt constant to get energy in eV.

3. Step 3: Check code correctness

   from scipy.constants import c, planck, electron_volt wavelength = 400e-9 energy_joule = planck * c / wavelength energy_ev = energy_joule / electron_volt print(round(energy_ev, 3)) correctly imports electron_volt, converts units properly, and prints rounded value. Other options either miss conversion, use wrong wavelength units, or wrong formula.

4. Final Answer:

   from scipy.constants import c, planck, electron_volt wavelength = 400e-9 energy_joule = planck * c / wavelength energy_ev = energy_joule / electron_volt print(round(energy_ev, 3)) -> Option B

5. Quick Check:

   Energy (eV) = (h*c/wavelength)/electron_volt [OK]

Hint: Convert joules to eV by dividing by electron_volt constant [OK]

Common Mistakes:

• Skipping conversion from joules to eV
• Using wavelength in nm without converting to meters
• Multiplying instead of dividing for energy calculation