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3 years ago

8

Light with a wavelength of 400 nm strikes the surface of cesium in a photocell, and the maximum kinetic energy of the electrons

ejected is 1.54 x 10‐19J. Calculate the longest wavelength of light that is capable of ejecting electrons from that metal. (1 nm = 10‐9 m)

1 answer:

Firdavs [7]3 years ago

8 0

Answer:

The longest wavelength of light that is capable of ejecting electrons from that metal is 1292 nm.

Explanation:

Given that,

Wavelength = 400 nm

Energy $E=1.54\times10^{-19}\ J$

We need to calculate the longest wavelength of light that is capable of ejecting electrons from that metal

Using formula of energy

$E = \dfrac{hc}{\lambda}$

$\lambda=\dfrac{hc}{E}$

Put the value into the formula

$\lambda=\dfrac{6.63\times10^{-34}\times3\times10^{8}}{1.54\times10^{-19}}$

$\lambda=1292\times10^{-9}\ m$

$\lambda=1292\ nm$

Hence, The longest wavelength of light that is capable of ejecting electrons from that metal is 1292 nm.

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Part a)

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Part b)

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Part c)

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Explanation:

Part a)

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so fractional loss in energy is given as

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Part b)

Let say the collision between Camel and the car is elastic collision

So here we can use momentum conservation

$m_1v_{1i} = m_1v_{1f} + m_2v_{2f}$

$1000 v_o = 1000 v_{1f} + 300 v_{2f}$

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now we have

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now we have

$v_{1f} = \frac{7v_o}{13}$

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$\Delta K = \frac{1}{2}m(v_o^2 - v_{1f}^2)$

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$f = \frac{120}{169}$

Part c)

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