Unit conversion utilities in SciPy - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of unit conversion using scipy.constants

What is the output of this code snippet that converts 10 kilometers to meters using scipy.constants?

SciPy

from scipy.constants import kilo
value_km = 10
value_m = value_km * kilo
print(value_m)

A 10000.0

B 10.0

C 0.01

D 1000.0

💡 Hint

Remember that 'kilo' in scipy.constants means 1000.

The 'kilo' constant equals 1000. Multiplying 10 kilometers by 1000 converts it to meters: 10 * 1000 = 10000.

❓ data_output

intermediate

Convert array of temperatures from Celsius to Kelvin

Given an array of temperatures in Celsius, what is the resulting array after converting to Kelvin using numpy and scipy.constants?

SciPy

import numpy as np
from scipy.constants import zero_Celsius
celsius_temps = np.array([0, 25, 100])
kelvin_temps = celsius_temps + zero_Celsius
print(kelvin_temps)

A [-273.15 -248.15 -173.15]

B [0 25 100]

C [273 298 373]

D [273.15 298.15 373.15]

💡 Hint

Add 273.15 to Celsius to get Kelvin.

The constant zero_Celsius equals 273.15. Adding it to Celsius temps converts them to Kelvin.

❓ visualization

advanced

Plotting unit conversions for length scales

Which option produces a plot showing meters converted to kilometers and centimeters correctly?

SciPy

import matplotlib.pyplot as plt
from scipy.constants import kilo, centi
lengths_m = [1, 5, 10]
lengths_km = [x / kilo for x in lengths_m]
lengths_cm = [x / centi for x in lengths_m]
plt.plot(lengths_m, lengths_km, label='km')
plt.plot(lengths_m, lengths_cm, label='cm')
plt.xlabel('Meters')
plt.ylabel('Converted Lengths')
plt.legend()
plt.show()

A Scatter plot with kilometers values larger than meters values

B Bar chart with meters, kilometers, and centimeters all equal values

C Line plot with meters on x-axis, kilometers and centimeters on y-axis, showing km values smaller than meters and cm values larger than meters

D Line plot with kilometers and centimeters both smaller than meters values

💡 Hint

Remember 1 meter = 0.001 kilometers and 100 centimeters.

Kilometers are larger units than meters (1m = 0.001km), centimeters are smaller (1m = 100cm). The plot must reflect this.

🔧 Debug

advanced

Identify the error in unit conversion code

What is the error in this code when converting 5 grams to kilograms using scipy.constants?

SciPy

from scipy.constants import kilo
mass_g = 5
mass_kg = mass_g * kilo
print(mass_kg)

A The output is 5000.0, which is incorrect for grams to kilograms conversion

B NameError because 'kilo' is not imported

C TypeError because you cannot multiply int by float

D No error, output is 0.005

💡 Hint

Check the meaning of 'kilo' and the units involved.

Multiplying grams by 1000 (kilo) converts grams to milligrams, not kilograms. The output 5000.0 is wrong for grams to kilograms.

🚀 Application

expert

Calculate energy in electronvolts from joules using scipy.constants

Which option correctly calculates the energy in electronvolts (eV) from 3.2e-19 joules using scipy.constants?

SciPy

from scipy.constants import electron_volt
energy_joules = 3.2e-19
energy_ev = energy_joules / electron_volt
print(energy_ev)

A 1.6e-19

B 2.0

C 3.2e-19

D 5.0

💡 Hint

1 electronvolt equals 1.6e-19 joules.

Dividing 3.2e-19 joules by 1.6e-19 joules/eV gives 2 eV.