Which of the following occurs with both a cold front and a mountain breeze?

A silver wire has a cross sectional area a = 2.0 mm2. a total of 9.4 × 1018 electrons pass through the wire in 3.0 s. the conduc

marta [7]

This problem uses the relationships among current I, current density J, and drift speed vd. We are given the total of electrons that pass through the wire in t = 3s and the area A, so we use the following equation to to find vd, from J and the known electron density n, so:

$v_{d} = \frac{J}{n\left | q \right |}$

<span>The current I is any motion of charge from one region to another, so this is given by:

</span> $I = \frac{\Delta Q}{\Delta t} = \frac{9.4x1018electrons}{3s} = 3189.73(A)$

The magnitude of the current density is:

$J = \frac{I}{A} = \frac{3189.73}{2x10^{-6}} = 1594.86(A/m^{2})$

Being:

$A=2mm^{2} = 2x10^{-6}m^{2}$
<span>
Finally, for the drift velocity magnitude vd, we find:

</span> $v_{d} = \frac{1594.86}{5.8x1028\left |1.60x10^{-19}|\right } = 1.67x10^{18}(m/s)$

Notice: The current I is very high for this wire. The given values of the variables are a little bit odd

6 0

3 years ago

a shell fired from a cannon at 60 ° from horizontal strikes a target 20m high at a distance 80m. Calculate the initial velocity

stich3 [128]

consider the motion along the X-direction

X = horizontal displacement = 80 m

$V_{ox}$ = initial velocity along the x-direction = v Cos60

t = time of travel

using the equation

X = $V_{ox}$ t

80 = (v Cos60) (t)

t = 160/v eq-1

consider the motion in vertical direction :

Y = vertical displacement = 20 m

$V_{oy}$ = initial velocity in Y-direction = v Sin60

a = acceleration = - 9.8 m/s²

t = time of travel = 160/v

using the equation

Y = $V_{oy}$ t + (0.5) a t²

20 = (v Sin60) (160/v) + (0.5) (- 9.8) (160/v)²

v = 32.5 m/s

4 0

3 years ago

According to the diagram, which color of visible light has the shortest wavelength?

Fynjy0 [20]

Answer:

Violet Light

Explanation:

On one end of the spectrum is red light, with the longest wavelength. Blue or violet light has the shortest wavelength. White light is a combination of all colors in the color spectrum. It has all the colors of the rainbow.

6 0

3 years ago

Read 2 more answers

An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its pla

dusya [7]

Answer:

C). $U_f = \frac{U_0}{2}$

Explanation:

As we know that capacitance of a given capacitor is

$C = \frac{\epsilon_0 A}{d}$

now we know that energy stored in the capacitor plates

$U_0 = \frac{Q^2}{2C}$

here if all the dimensions of the capacitor plate is doubled

then in that case

$C' = \frac{\epsilon_0 (4A)}{2d}$

here area becomes 4 times on doubling the radius and the distance between the plates also doubles

So new capacitance is now

$C' = 2C$

so capacitance is doubled

now the final energy stored between the plates of capacitor is given as

$U_f = \frac{Q^2}{2C'}$

so the final energy is

$U_f = \frac{Q^2}{4C}$

$U_f = \frac{U_0}{2}$

4 0

3 years ago

A hypothesis that survives peer review receiving similar results and has predictive capabilities a Fact a) Theory b) a Law an Ax

MaRussiya [10]

Answer:

The correct answer will be option-B.

Explanation:

A scientific hypothesis is the proposed perdition or idea which is based on the earlier works and knowledge related to the scientific issue. The hypothesis can be tested and proved on the basis of the experiments.

The proved hypothesis can either become law or theory after peer-reviewed by fellow scientists. If the hypothesis still has predictive capabilities help form another hypothesis. Such statements are known as the "theory".

Thus, Option-B is the correct answer.

5 0

3 years ago