HELP ASAP PLEASE!!!

Which of the following metals require ultraviolet light to exhibit the photoelectric effect?The options available: a. Cs, work f

Eddi Din [679]

Answer:

b. AG, work function=4.74eV

Explanation:

Ultraviolet light starts at the end of the visible light spectrum, where violet light ends:

$\lambda=380 nm =3.8\cdot 10^{-7}m$ (wavelength of lowest-energy ultraviolet light)

So, the lowest energy of ultraviolet light can be found by using the formula

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

where

h is the Planck constant

c is the speed of light

Substituting,

$E=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{3.8\cdot 10^{-7} m}=5.23\cdot 10^{-19}J$

And keeping in mind that

$1 eV = 1.6\cdot 10^{-19}J$

This energy converted into electronvolts is

$E=\frac{5.23\cdot 10^{-19} J}{1.6\cdot 10^{-19} J/eV}=3.27 eV$

The work function of a metal is the minimum energy needed to extract a photoelectron from the surface of the metal. Therefore, the metals that exhibit photoelectric effect are the ones whose work function is larger than the energy we found previously, so:

b. AG, work function=4.74eV

Because for all the other metals, visible light will be enough to extract photoelectrons.

7 0

3 years ago

Which philosopher suggested that the mind and body are separate but that a link exists between them?

hammer [34]

<span>René Descartes suggests this.</span>

7 0

3 years ago

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8. Two forces of 10 N and 30 N are applied to a 10 kg box. Find (1) the box’s acceleration when both forces point due east and (

love history [14]

(1) acceleration, a = 4 m/ $s^{2}$ (2) acceleration of 10 N, $a_{1}$ = 1 m/ $s^{2}$ and acceleration of 30 N, $a_{2}$ = 3 m/ $s^{2}$

Explanation:

Here, the acceleration of the object could be found using the equation derived in the second law of motion. The equation is given as, F = ma where m is the acceleration of the object, m is the mass of the object and F is the applied on the object.
Let $a_{1}$ be the acceleration for force 10 N, to find acceleration rearrange the equation to a = $\frac{F}{m}$ . When we substitute 10 N force and 10 kg mass of the box in the equation. We will get $a_{1}$ = 1 m/ $s^{2}$

Let $a_{2}$ be the acceleration for force 30 N, to find acceleration rearrange the equation to F = $\frac{F}{m}$ . When we substitute 30 N force and 10 kg mass of the box in the equation. We will get $a_{2}$ = 3 m/ $s^{2}$
To find the combined, just add the force and substitute in the above equation. Hence, a = 4 m/ $s^{2}$

3 0

2 years ago

What is the effective resistance between the points A and D? A) 1.3 Ω B) 2.2 Ω C) 10 Ω D) 12 Ω

Rudiy27

Answer:

B) 2.2 Ω

Explanation:

First of all, we should notice that the resistor placed between A and B is short-circuited. In fact, the current from point A will follow the wire above between A and C (which has zero resistance), so we can basically ignore the presence of the resistor between A and B, since it has no effect on the circuit.

Then, we can notice that the two resistors between CB and CD are in parallel to each other; therefore, their equivalent resistance is given by:

$\frac{1}{R}=\frac{1}{R_{BC}}+\frac{1}{R_{CD}}=\frac{1}{4.0 \Omega}+\frac{1}{5.0 \Omega}=\frac{9}{20 \Omega}\\R= \frac{20 \Omega}{9}=2.2 \Omega$

6 0

3 years ago

What is 9 plus -2.00 ?

kobusy [5.1K]

The answer is 7.........

5 0

3 years ago

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