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The equation for energy (E) of a simple ...

The equation for energy (E) of a simple harmonic oscillator, `E = (1)/(2) mv^(2)+(1)/(2)+ omega^(2)x^(2)`?, is to be made "dimensionless" by multiplying by a suitable factor, which may involve the constants, m(mass), `omega`(angular frequency) and h(Planck's constant). What will be the unit of momentum and length?

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To solve the problem of making the energy equation of a simple harmonic oscillator dimensionless, we need to determine the units of momentum and length based on the constants involved: mass (m), angular frequency (ω), and Planck's constant (h). ### Step-by-Step Solution: 1. **Identify the Energy Equation**: The energy (E) of a simple harmonic oscillator is given by: \[ E = \frac{1}{2} mv^2 + \frac{1}{2} kx^2 \] where \( k = m\omega^2 \) for a harmonic oscillator. 2. **Express the Energy in Terms of Dimensions**: The dimensions of each term in the energy equation can be expressed as follows: - The dimension of mass \( m \) is \( [M] \). - The dimension of velocity \( v \) is \( [L][T^{-1}] \). - Therefore, the dimension of \( mv^2 \) is: \[ [M][L^2][T^{-2}] \] - The dimension of \( kx^2 \) (where \( k = m\omega^2 \)) is also \( [M][L^2][T^{-2}] \). 3. **Planck's Constant**: The dimension of Planck's constant \( h \) is given by: \[ [h] = [E][T] = [M][L^2][T^{-2}][T] = [M][L^2][T^{-1}] \] 4. **Determine the Dimensions of \( m\omega h \)**: - The angular frequency \( \omega \) has dimensions of \( [T^{-1}] \). - Therefore, the dimensions of \( m\omega h \) are: \[ [M][T^{-1}][M][L^2][T^{-1}] = [M^2][L^2][T^{-2}] \] 5. **Momentum**: The momentum \( p \) is defined as: \[ p = mv \] Thus, the dimensions of momentum are: \[ [M][L][T^{-1}] \] 6. **Length**: To find a suitable expression for length in terms of \( m \), \( \omega \), and \( h \), we can consider: \[ L = \frac{h}{m\omega} \] The dimensions of this expression can be derived as follows: - The dimension of \( h \) is \( [M][L^2][T^{-1}] \). - The dimension of \( m\omega \) is: \[ [M][T^{-1}] \] - Therefore, the dimensions of \( L \) become: \[ \frac{[M][L^2][T^{-1}]}{[M][T^{-1}]} = [L^2] \] - Taking the square root gives us the dimension of length \( [L] \). ### Final Expressions: - The unit of momentum is \( [M][L][T^{-1}] \). - The unit of length is \( \frac{h}{m\omega} \).
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Knowledge Check

  • The dimension of the quantity 1/epsilon_0 e^2/(hc) is (e charge of electron,h Planck's constant and c=velocity of light)

    A
    `[M^(-1) L^(-3) T^2 A]`
    B
    `[M^(0) L^(0) T^0 A^0]`
    C
    `[ML^(3) T^(-4) A^(-2)]`
    D
    `[M^(-1) L^(-3) T^4 A^2]`
  • A simple harmonic oscillator has a frequency of 2.5 Hz and an amplitude of 0.05m. What is the period of the oscillations?

    A
    0.4s
    B
    0.2s
    C
    8s
    D
    20s
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