Determine the number of significant figures.

A light source of wavelength, l, illuminates a metal and ejects photoelectrons with a maximum kinetic energy of 1 eV. A second l

madreJ [45]

Explanation:

From first source, kinetic energy ( $K.E_{1}$ ) ejected is 1 eV and wavelength of light is $\lambda$ .

From second source, kinetic energy ( $K.E_{2}$ ) ejected is 4 eV and wavelength of light is $\frac{\lambda}{2}$ .

Relation between work function, wavelength, and kinetic energy is as follows.

K.E = $\frac{hc}{\lambda} - \phi$

where, h = Plank's constant = $6.63 \times 10^{-34}$ J.s

c = speed of light = $3 \times 10^{8}$ m/s

Also, it is known that 1 eV = $1.6 \times 10^{-19}$ J

Therefore, substituting the values in the above formula as follows.

From first source,

$K.E_{1}$ = $\frac{hc}{\lambda} - \phi$

1 eV = $1.6 \times 10^{-19} J = \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{\lambda} - \phi$

$1.6 \times 10^{-19} J = \frac{1.98 \times 10^{-25} J.m}{\lambda} - \phi$ ........... (1)

From second source,

$K.E_{2}$ = $\frac{hc}{\lambda} - \phi$

$4 \times 1.6 \times 10^{-19} J = \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{\frac{\lambda}{2}} - \phi$

$6.4 \times 10^{-19} J = \frac{2 \times 1.98 \times 10^{-25} J.m}{\lambda} - \phi$ ........... (2)

Now, divide equation (2) by 2. Therefore, it will become

${6.4 \times 10^{-19}J}{2} = \frac{2 \times 1.98 \times 10^{-25} J.m}{2\lambda} - \frac{\phi}{2}$

$3.2 \times 10^{-19}J = \frac{1.98 \times 10^{-25} J.m}{\lambda} - \frac{\phi}{2}$ ......... (3)

Now, subtract equation (3) from equation (1), we get the following.

$1.6 \times 10^{-19} = \frac{\phi}{2}$

$\phi$ = $3.2 \times 10^{-19}$

= 2 eV

Thus, we can conclude that work function of the metal is 2 eV.

3 0

4 years ago

Why is it important to clean and care for cuts on your skin

alukav5142 [94]

If one does not do so, the cut can lead to being infected with various pathogens and other Bacteria, possibly worsening the Minor injury. Thus taking additional medication and further required time to heal.

6 0

4 years ago

Can you show me the answer and explain?

Hitman42 [59]

Answer:

C

Explanation:

looking at a periodic table X is fluorine and Y is potassium

Fluorine is in group 7 and forms a 1- charge (which gains electrons) and potassium is in group 1 and forms a 1+ charge (which loses electrons)

Fluorine (X) has an electronic structure of 2,7 and needs to gain an electron from Potassium (Y) to have a full outer shell and potassium has an electronic structure of 2,8,8,1 so needs to lose an electron to have a full outer shell as well. This means that the electron that potassium (Y) has lost is given away to fluorine (X), so both elements become stable.

This is known as ionic bonding where metals (like potassium) lose electrons and non-metals (like fluorine) gain electrons to become more stable, forming ions

Any further clarification let me know

6 0

2 years ago

Heat required to raise 1 g of a substance 1°C

Oksana_A [137]

Answer:

Specific heat

Explanation:

7 0

3 years ago

Natural vs. Synthetic

myrzilka [38]

Answer:

Natural chemicals are produced by nature without any human intervention. Synthetic chemicals are made by humans using methods different than those nature uses, and these chemical structures may or may not be found in nature. Stay safe .

8 0

3 years ago

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