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Karl asked in Science & MathematicsPhysics · 7 years ago

How to get the value of Rydberg's constant (R) and n_2?

Based from the formula

1/λ = R ( 1/ (n_2)^2 - 1/(n_1)^2 )

If I get the graph of 1/λ (y-axis) vs. 1/(n_1)^2 (x-axis), how do I get the value of R based from the slope and n_2 based from the y-intercept? Thank you :D

1 Answer

  • 7 years ago
    Favorite Answer

    1/λ = R (1/n₂² - 1/n₁²)

    1/λ = R/n₂² - R(1//n₁²) (equation 1)

    You need to be sure which quantities are variables and which are constants.

    1/λ and 1/n₁² are variable quantities

    R and 1/n₂² are constants.

    Compare equation 1 to y = c + mx and you can see:

    - the variable y is equivalent to 1/λ

    - the variable x is equivalent to 1/n₁²

    - the constant m is equivalent to -R

    - the constant c is equivalent to R/n₂²

    FInd the gradient (which should be negative); since gradient = -R, R = - gradient.

    Find the 1/λ intercept and then use:

    Intercept = R/n₂²

    n₂ = √(R/intercept)

    n₂ should work out to be (close to) an integer.

    If you are using SI units, make sure λ is in metres, so 1/λ has units of m⁻¹ by the way.

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