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3 years ago

What do we mean by the event horizon of a black hole?

Physics

1 answer:

Fynjy0 [20]3 years ago

6 0

The correct answer is: C. It is the point beyond which neither light nor anything else can escape.

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For copper, ρ = 8.93 g/cm3 and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electro

viktelen [127]

Answer:

$V_d$ = 1.75 × 10⁻⁴ m/s

Explanation:

Given:

Density of copper, ρ = 8.93 g/cm³

mass, M = 63.5 g/mol

Radius of wire = 0.625 mm

Current, I = 3A

Area of the wire, $A = \frac{\pi d^2}{4}$ = $A = \frac{\pi 0.625^2}{4}$

Now,

The current density, J is given as

$J=\frac{I}{A}=\frac{3}{ \frac{\pi 0.625^2}{4}}$ = 2444619.925 A/mm²

now, the electron density, $n = \frac{\rho}{M}N_A$

where,

$N_A$ =Avogadro's Number

$n = \frac{8.93}{63.5}(6.2\times 10^{23})=8.719\times 10^{28}\ electrons/m^3$

Now,

the drift velocity, $V_d$

$V_d=\frac{J}{ne}$

where,

e = charge on electron = 1.6 × 10⁻¹⁹ C

thus,

$V_d=\frac{2444619.925}{8.719\times 10^{28}\times (1.6\times 10^{-19})e}$ = 1.75 × 10⁻⁴ m/s

4 0

3 years ago

Read 2 more answers

I need so much help 50 points!!!!!! complete the graph

motikmotik

First Symbol : Cobalt (Co)

Its Group Number - 9

Its Period Number - 4

Its Family Name - Transition Metal

Second Symbol : Silicon (Si)

Its Group Number - 14

Its Period Number - 2

Its Family Name - Semiconductor

Third Symbol : Astatine (At)

Its Group Number - 17

Its Period Number - 6

Its Family Name - Halogen

Fourth Symbol : Magnesium (Mg)

Its Group Number - 2

Its Period Number - 3

Its Family Name - Alkaline Earth Metal

Fifth Symbol : Xenon (Xe)

Its Group Number - 18

Its Period Number - 5

Its Family Name - Noble Gas

6 0

3 years ago

On Monday, Jacques announces to his parents that he wants to be called "Jack." On Wednesday, he says he wants to drop out of sch

Alex777 [14]

Jaques seems to be in the Rebelious stage

5 0

4 years ago

Any fracture or system of fractures along which Earth moves is known as a

Alexxx [7]

Any fracture or system of fractures along which Earth moves is known as a fault.

Answer: b. fault.

5 0

3 years ago

Calculate the pressure exerted on the ground by a boy of a mass 60 kg if he stands on one foot.the area of the sole of his shoe

ddd [48]

Answer:

40 Kpa

Explanation:

150 cm2 = 0.015 m2

$p \: = \frac{mg}{ a} = 40000$

8 0

3 years ago