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vovikov84 [41]
3 years ago
9

The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275 kj/mol. What wavelength in nm of

light has sufficient energy per photon to dislodge an electron from the surface of sodium?
Physics
1 answer:
denis23 [38]3 years ago
7 0

Answer: 430 nm

Explanation:

For 257 kJ to dislodge one mole of electrons we need,

275 x 10^3 / 6 x 10^23 = 4.6 x 10^-19

Using Einstein’s relationship between energy, frequency and wavelength

E = hf = h x (c/landa)

Therefore

Landa = h x (c/E) = 6.6 x 10^-34 x (3 x 10^8 / 4.6 x 10^-19 = 4.3 x 10-7 m.

In nm, landa = 430 nm

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A penny is dropped from the top of a 180m building. How much time will it take to fall to the ground?
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180 cm3 of hot tea at 97 °C are poured into a very thin paper cup with 20 g of crushed ice at 0 °C. Calculate the final temperat
Zolol [24]

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c_1 = specific heat of hot water (liquid) = 4.18J/g^oC

c_2 = specific heat of ice (solid)= 2.10J/g^oC

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m_2 = mass of ice = 20 g

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T_1 = initial temperature of hot water = 97^oC

T_2 = initial temperature of ice = 0^oC

Now put all the given values in the above formula, we get

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T_f=91.9^oC

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The rectilinear motion is given as:

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