2 years ago

determine if the pennies are made of pure copper by comparing the density with that of the pure copper

1 answer:

4 0

Answer:

The pennies are NOT made of pure copper since the obtained density is 9.29 g/cm3 which is greater than the density of copper which is 8.96 g/cm3.

Explanation:

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If the wavelength of purple light is 400 x 10^-9 m, what is the frequency?

FromTheMoon [43]

The frequency : a) 7.5 x 10¹⁴ /s

<h3>Further explanation</h3>

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

$\large{\boxed{\bold{E\:=\:h\:.\:f}}}$

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves (/s or Hz)

f = c / λ

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= 3.10⁸ m/s

λ = wavelength

The wavelength(λ) of purple light is 400 x 10⁻⁹ m, so the frequency :

$\tt f=\dfrac{c}{\lambda}\\\\f=\dfrac{3.10^8~m/s}{4.10^{-7}m}\\\\f=\boxed{\bold{7.5.10^{14}}/s}$

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