# Problem: 1. In SI units, 1 volt = 1 joule/coulomb. If an electron-volt (eV) is equal to the energy of 1 electron moved through a potential difference of 1 volt, how many joules is this? (Hint: what is the charge of one electron?)2. A terahertz (THz) is 1012 hertz (Hz), and 1 Hz = 1 s-1. How many joule-seconds is 1 eV/THz?3. Express Planck's constant h in units of eV/THz.4. Express the number (0.5 eV)/(100 THz) in J-s.

###### FREE Expert Solution

Energy and potential are related by:

$\overline{){\mathbf{E}}{\mathbf{=}}{\mathbf{q}}{\mathbf{V}}}$, where q is the charge of an electron, in this case, and V is the electric potential.

Energy, in terms of frequency, can also be expressed as:

$\overline{){\mathbf{E}}{\mathbf{=}}{\mathbf{h}}{\mathbf{v}}}$, where h is Plank's constant and v is the frequency.

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###### Problem Details

1. In SI units, 1 volt = 1 joule/coulomb. If an electron-volt (eV) is equal to the energy of 1 electron moved through a potential difference of 1 volt, how many joules is this? (Hint: what is the charge of one electron?)

2. A terahertz (THz) is 1012 hertz (Hz), and 1 Hz = 1 s-1. How many joule-seconds is 1 eV/THz?

3. Express Planck's constant h in units of eV/THz.

4. Express the number (0.5 eV)/(100 THz) in J-s.