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3 years ago

‏Explain how an electron emitted by the photoelectric effect can have kinetic energy less than threshold energy ?

Physics

1 answer:

xenn [34]3 years ago

4 0

Answer:

the photons (quanta of light) collide with the electrons, these electrons have to overcome the threshold energy that is the energy of union with the metal, and the energy that remains is converted to kinetic energy.

K = E - Ф

Explanation:

The photoelectric effect is the emission of electrons from the surface of a metal.

This was correctly explained by Einstein, in his explanation the energy of the photons (quanta of light) collide with the electrons, these electrons have to overcome the threshold energy that is the energy of union with the metal, and the energy that remains is converted to kinetic energy.

E = hf

E = K + Ф

K = E - Ф

The energy of the photons is given by the Planck relation E = hf and according to Einstein the number of joints must be added

E = n hf

Therefore, depending on the value of this energy, the emitted electrons can have energy from zero onwards.

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When placed 1.18 m apart, the force each exerts on the other is 11.2 N and is repulsive. What is the charge on each

aleksandr82 [10.1K]

Answer:

$q=41.62\ \mu C$

Explanation:

Given that,

Force between two objects, F = 11.2 N

Distance between objects, d = 1.18 m

We need to find the charge on each objects. The force between charges is as follows :

$F=\dfrac{kq^2}{r^2}\\\\q=\sqrt{\dfrac{Fr^2}{k}} \\\\q=\sqrt{\dfrac{11.2\times (1.18)^2}{9\times 10^9}} \\\\q=41.62\ \mu C$

So, the charge on each sphere is $41.62\ \mu C$ .

7 0

3 years ago

Doppler Effect: A stationary source produces a sound wave at a frequency of 50 Hz. The wave travels at 100 feet per second. A ca

Leno4ka [110]

Answer:

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︎

︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎

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︎ ︎ ︎︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎ ︎

Explanation:

Hope it helps!

6 0

3 years ago

Explain how the distance to a lightning bolt (Fig. CQ17.5) can be determined by counting the seconds between the flash and the s

Sonbull [250]

The distance to a lightning bolt can be determined by counting the seconds between the flash and the sound of thunder due to the speed of light is greater than the speed of sound

We must consider that the speed of light (3.00× 10⁸ m/s) is greater than the speed of sound (340 m/s), this is why we can first see the lightning and after seeing it we can hear it.

In order to calculate the distance we must count the time since the lightning bolt and use the speed of sound, applying the following formula:

x = v * t

Where:

x = distance
t = time
v = velocity

<h3>What is velocity?</h3>

It is a physical quantity that indicates the displacement of a mobile per unit of time, it is expressed in units of distance per time, for example (miles/h, km/h).

Learn more about velocity at: brainly.com/question/80295?source=archive

#SPJ4

7 0

2 years ago

Compute the resistance in ohms of a silver block 10 cm long and 0.10 cm2 in cross-sectional area. ( = 1.63 x 10-6 ohm-cm)

Vedmedyk [2.9K]

The resistance of the silver block is given by
$R= \frac{\rho L}{A}$
where
$\rho=1.63 \cdot 10^{-6} \Omega \cdot cm$ is the silver resistivity
$L=10 cm$ is the length of the block
$A=0.10 cm^2$ is the cross-sectional area of the block

If we plug the data into the equation, we find the resistance of the silver block:
$R= \frac{(1.63 \cdot 10^{-6} \Omega \cdot cm)(10 cm)}{0.10 cm^2}=1.63 \cdot 10^{-4} \Omega$

3 0

4 years ago

A transverse wave on a string is described by the wave functiony(x, t) = 0.350 sin (1.25x + 99.6t)where x and y are in meters an

ella [17]

The time interval that is between the first two instants when the element has a position of 0.175 is 0.0683.

<h3>How to solve for the time interval</h3>

We have y = 0.175

y(x, t) = 0.350 sin (1.25x + 99.6t) = 0.175

sin (1.25x + 99.6t) = 0.175

sin (1.25x + 99.6t) = 0.5

99.62 = pi/6

t1 = 5.257 x 10⁻³

99.6t = pi/6 + 2pi

= 0.0683

The time interval that is between the first two instants when the element has a position of 0.175 is 0.0683.

b. we have k = 1.25, w = 99.6t

v = w/k

99.6/1.25 = 79.68

s = vt

= 79.68 * 0.0683

= 5.02