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4 years ago

8

An electron in a TV picture tube is accelerated through a potential difference of 10 kV before it hits the screen. What is the k

inetic energy of the electron in electron volts?(1 eV = 1.6 ? 10 -19 J)

1 answer:

laiz [17]4 years ago

7 0

Answer:

10,000 eV

Explanation:

According to the law of conservation of energy, the kinetic energy gained by the electron is equal to its change in electric potential energy:

$K=\Delta U=q \Delta V$

where:

K is the kinetic energy of the electron

$q=1 e$ is the magnitude of the charge of the electron

$\Delta V$ is the potential difference through which the electron has been accelerated

For this electron in the TV, we have

$\Delta V=10 kV=10000 V$

Therefore, the kinetic energy of the electron in electronvolts is

$K=(1 e)(10000 V)=10000 eV$

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Explanation:

vfv g bygyb

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3 years ago

Which measurement is a potential difference?<br> A.115J<br> B.115V<br> C.115N<br> D.115C

borishaifa [10]

Answer:

B

Explanation:

Potential difference has a SI Unit of Volt and its symbol is <em>V</em>. Hence answer is <u>B</u>.

A is wrong as it has the unit Joule <em>(J)</em> which is the SI unit for energy.

C is wrong as it has the unit Newton <em>(N)</em> which is the SI unit for force.

D is wrong as it has the unit Coulomb <em>(C)</em> which is the SI unit of charge.

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4 years ago

Ms. Kasper is in a panic. Her cat, Penny, is stuck in a tree and about to jump out. In order to save her cat, Ms. Kasper needs t

Misha Larkins [42]

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Given that Ms. Kasper is in a panic. Her cat, Penny, is stuck in a tree and about to jump out. In order to save her cat, Ms. Kasper needs to run to the tree, 12 meters away. If it takes her cat, 3 seconds to fall, how fast would Ms. Kasper have to run to save her cat?

The distance = 12 m

Time = 3s

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Ms Kasper must run at speed more than 4m/s for her to save the cat.

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3 years ago

Gravity on earth is 9.8 m/s squared, and gravity on the moon is 1.6 m/s squared. So if the mass of an object on earth is 40 kilo

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The mass of an object on Earth is the same as its mass on the Moon. The weight is different.

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3 years ago

A soccer player takes a corner kick, lofting a stationary ball 30.0° above the horizon at 18.0 m/s. If the soccer ball has a mas

Radda [10]

Answer:

change in momentum, $\Delta p=7.65 \,kg.m.s^{-1}$

$\Delta p_x= 6.6251 \,kg.m.s^{-1}$

$\Delta p_y= 3.825 \,kg.m.s^{-1}$

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$F_x=125.0018\,N$

$F_y=72.1698\,N$

Explanation:

Given:

angle of kicking from the horizon, $\theta= 30^{\circ}$

velocity of the ball after being kicked, $v=18 m.s^{-1}$

mass of the ball, $m=0.425\, kg$

time of application of force, $t=5.3\times 10^{-2}\,s$

We know, since body is starting from the rest

$\Delta p=m.v$ .....................(1)

$\Delta p=0.425\times 18$

$\Delta p=7.65 \,kg.m.s^{-1}$

Now the components:

$\Delta p_x= 7.65\times cos 30^{\circ}$

$\Delta p_x= 6.6251 \,kg.m.s^{-1}$

similarly

$\Delta p_y= 7.65\times sin 30^{\circ}$

$\Delta p_y= 3.825 \,kg.m.s^{-1}$

also, impulse

$I=F\times t$ .........................(2)

where F is the force applied for t time.

Then from eq. (1) & (2)

$F\times t=m.v$

$F\times 5.3\times 10^{-2}= 7.65$

$F=144.3396\,N$

Now, the components

$F_x=144.3396\times cos 30^{\circ}$

$F_x=125.0018\,N$

&

$F_y=144.3396\times sin 30^{\circ}$

$F_y=72.1698\,N$

6 0

3 years ago