Can anyone explain and get the answer pls?

When light of wavelength 240 nm falls on a cobalt surface, electrons having a maximum kinetic energy of 0.17 eV are emitted. Fin

dusya [7]

Answer:

(a) 5.04 eV (B) 248.14 nm (c) $1.21\times 10^{15}Hz$

Explanation:

We have given Wavelength of the light \lambda = 240 nm

According to plank's rule ,energy of light

$E = h\nu = \frac{hc}{}\lambda$

$E = h\nu = \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{ 240\times 10^{-9} m\times 1.6\times 10^{-19}J/eV}= 5.21 eV$

Maximum KE of emitted electron i= 0.17 eV

Part( A) Using Einstien's equation

$E = KE_{max}+\Phi _{0}$ , here $\Phi _0$ is work function.

$\Phi _{0}=E - KE_{max}$ = 5.21 eV-0.17 eV = 5.04 eV

Part( B) We have to find cutoff wavelength

$\Phi _{0} = \frac{hc}{\lambda_{cuttoff}}$

$\lambda_{cuttoff}= \frac{hc}{\Phi _{0} }$

$\lambda_{cuttoff}= \frac{6.67\times 10^{-34} J.s\times 3\times 10^{8}m/s}{5.04 eV\times 1.6\times 10^{-19}J/eV }=248.14 nm$

Part (C) In this part we have to find the cutoff frequency

$\nu = \frac{c}{\lambda_{cuttoff}}= \frac{3\times 10^{8}m/s}{248.14 \times 10^{-19} m }= 1.21\times 10^{15} Hz$

5 0

3 years ago

What was Marie's speed from point A to point B, in miles/minute?

sveticcg [70]

Answer:

40m

Explanation:

40m

6 0

3 years ago

One type of potential energy is gravitational potential energy. What is necessary for an object to have gravitational potential

galben [10]

Answer:

Gravitational potential energy is energy an object possesses because of its position in a gravitational field. Since the force required to lift it is equal to its weight, it follows that the gravitational potential energy is equal to its weight times the height to which it is lifted.

5 0

3 years ago

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Which of the following is associated with fission but not fusion?

kodGreya [7K]

Answer:

D. Uranium

Explanation:

I just got the answer right on my quiz.

8 0

3 years ago

The speed of a car during a trip is represented in the graph. Compare distance and displacement at four hours into the trip.

mezya [45]

Answer:

The answer to your question is: D.

Explanation:

Distance refers to the amount of space between two points, it is a scalar quantity.

Displacement refers to the space between two points, measure from the minimum path linking them, it is a vector quantity.

I'm not agree with these answers, because the total distance is approximately 500km.

A) The distance traveled is 300 km. This answer is not correct.

B) Distance is 300 km and displacement is 0 km. This answer is not correct because the displacement is also 500 km.

C) Distance is 300 km/hour and displacement is 300 km. 300 km/h is a measure of speed not of distance, this option is wrong.

D) Both distance traveled and displacement are 300 km. I think this is the correct answer because distance and displacement measure the same. but I think both measure 500 km.

7 0

3 years ago

Read 2 more answers