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jekas [21]
3 years ago
5

Early black-and-white television sets used an electron beam to draw a picture on the screen. The electrons in the beam were acce

lerated by a voltage of 3.0 kV; the beam was then steered to different points on the screen by coils of wire that produced a magnetic field of up to 0.65 T .
What is the speed of electrons in the beam?
Physics
1 answer:
oee [108]3 years ago
3 0

Answer:

3.25 × 10^7 m/s

Explanation:

Assuming the electrons start from rest, their final kinetic energy is equal to the electric potential energy lost while moving through the potential difference (ΔV)

Ek = 1/2 mv2 = qΔV .................. 1

Given that V is the electron speed in m/s

Charge of electron = 1.60217662 × 10-19 coulombs

Mass of electron = 9.109×10−31 kilograms

ΔV = 3.0kV = 3000V

Make V the subject of the formula in eqaution 1

V = sqr root 2qΔV/m

V = 2 × 1.60217662 × 10-19 × 3000 / 9.109×10−31

V = 3.25 × 10^7 m/s

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If the input work on a machine is equal to it's output work. the machine has _____ efficiency.
AleksAgata [21]

Answer:

100% efficiency

Explanation:

the machine has _100%_ efficiency.

(fill in the blank)

7 0
3 years ago
Which statement best defines constructive interference? O Energy reflects back toward the source of its power. O Two waves with
Brums [2.3K]

Answer: two waves with identical crests and troughs meet

Explanation:

My teacher gave me the answer

4 0
2 years ago
A ball is thrown upward with a speed of 40 m/s. Approximately how much time does it take the ball to travel from the release loc
zvonat [6]

I'm going to assume that this gripping drama takes place on planet Earth, where the acceleration of gravity is 9.8 m/s².  The solutions would be completely different if the same scenario were to play out in other places.

A ball is thrown upward with a speed of 40 m/s.  Gravity decreases its upward speed (increases its downward speed) by 9.8 m/s every second.

So, the ball reaches its highest point after (40 m/s)/(9.8 m/s²) = <em>4.08 seconds</em>. At that point, it runs out of upward gas, and begins falling.

Just like so many other aspects of life, the downward fall is an exact "mirror image" of the upward trip.  After another 4.08 seconds, the ball has returned to the height of the hand which flung it.  In total, the ball is in the air for <em>8.16 seconds</em> up and down.

4 0
3 years ago
Need help ASAP
VARVARA [1.3K]

Answer:

the correct one is D,  

Ultraviolet, x-ray, gamma ray

Explanation:

Electromagnetism radiation are waves of energy that is expressed by the Planck relationship

          E = h f

where h is the plank constant and f the frequency of the radiation.

Also the speed of light is

          c = λ f

         

we substitute

          E = h c /λ

therefore to damage the cells of the body radiation of appreciable energy is needed

microwave radiation has an energy of 10⁻⁵ eV

infrared radiation                E = 10⁻² eV

visible radiation                   E = 1 to 3 eV

radiation Uv                         E = 3 to 6 eV

X-ray                                    E = 10 eV

 

gamma rays                         E = 10 5 eV

therefore we see that the high energy radiation is gamma rays, x-rays and ultraviolet light.

When checking the answers, the correct one is D

6 0
2 years ago
Put the following events in the order they occurred to lead to the formation of the solar system:
AfilCa [17]

Answer:

Third → First → Second → Fourth

Explanation:

Initially helium and Hydrogen in abundance started to form atoms

Following the atoms formation by hydrogen and helium bombardment of new matter into the Earth took place.

The bombardment of matter resulted in separation of Earth into respective layers based on the weight of the matter.

A primitive ocean was created as a result of off gassing of the volcanoes.

8 0
2 years ago
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