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3 years ago

Which of the following is the best thermal insulator

Physics

1 answer:

riadik2000 [5.3K]3 years ago

5 0

Answer: a. air

Explanation:

Generally, the lower the density of the material, the better insulator the material is: this is because in materials with very low density, particles are very spread apart, so they cannot collide with each other, and so the vibrations of the particles (which determine how hot a substance is) cannot be transmitted very efficiently.

In the options listed in this problem, air is the material with lowest density, therefore it is the best thermal insulator among them.

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As an electron moves, what does it make or cause ?

jolli1 [7]

It causes or makes a magnetic field.

3 0

3 years ago

Monochromatic light falls on two very narrow slits 0.046 mm apart. Successive fringes on a screen 6.20 m away are 8.9 cm apart n

Elanso [62]

Answer:

λ = 6.602 x 10^(-7) m

Explanation:

In a double-slit interference experiment, the distance y of the maximum of order m from the center of the observed interference pattern on the screen is given as ;

y = mλD/d

Where;

D is the distance of the screen from the slits = 6.2 m

d is the distance between the two slits = 0.046 mm = 0.046 x 10^(-3) m

The fringes on the screen are 8.9 cm = 0.089 m apart from each other, this means that the first maximum (m=1) is located at y = 0.089 m from the center of the pattern.

Therefore, from the previous formula we can find the wavelength of the light:

y = mλD/d

So, λ = dy/mD

Thus,

λ = (0.046 x 10^(-3) x 0.089)/(1 x 6.2)

λ = 6.602 x 10^(-7) m

8 0

3 years ago

Suppose an electron is trapped within a small region and the uncertainty in its position is 24.0 x 10-15 m. What is the minimum

Alina [70]

Answer:

Uncertainty in position (∆x) = 24 × 10⁻¹⁵ m
Uncertainty in momentum (∆P) = ?
Planck's constant (h) = 6.26 × 10⁻³⁴ Js

$\longrightarrow \: \: \sf\Delta x .\Delta p = \dfrac{h}{4\pi}$

$\longrightarrow \: \: \sf24 \times {10}^{ - 15} .\Delta p = \dfrac{6.26 \times {10}^{ - 34}} {4 \times \frac{22}{7} }$

$\longrightarrow \: \: \sf24 \times {10}^{ - 15} .\Delta p = \dfrac{6.26 \times {10}^{ - 34}} { \frac{88}{7} }$

$\longrightarrow \: \: \sf24 \times {10}^{ - 15} .\Delta p = \dfrac{6.26 \times {10}^{ - 34} \times 7} { 8 }$

$\longrightarrow \: \: \sf\Delta p = \dfrac{43.82 \times {10}^{ - 34} } { 8 \times 24 \times {10}^{ - 15} }$

$\longrightarrow \: \: \sf\Delta p = \dfrac{43.82 \times {10}^{ - 34} } { 192 \times {10}^{ - 15} }$

$\longrightarrow \: \: \sf\Delta p = \dfrac{43.82 \times {10}^{ - 34} \times {10}^{15} } { 192}$

$\longrightarrow \: \: \sf\Delta p = \dfrac{43.82 \times {10}^{ -19} } { 192}$

$\longrightarrow \: \: \sf\Delta p = \dfrac{4382 \times {10}^{ - 2} \times {10}^{ -19} } { 192}$

$\longrightarrow \: \: \sf\Delta p = \dfrac{4382 \times {10}^{ - 21} } { 192}$

$\longrightarrow \: \: \sf\Delta p = 22.822\times {10}^{ - 21}$

$\longrightarrow \: \: \sf\Delta p = 2.2822 \times {10}^{1} \times {10}^{ - 21}$

$\longrightarrow \: \: \underline{ \boxed{ \red{ \bf\Delta p = 2.2822 \times {10}^{ - 20} \: kg/ms}}}$

4 0

3 years ago

In the national grid,what does the step up transformer do?

amm1812

In the National Grid, the Step Up Transformer increases the amount of voltage that is passing through the grid at any one time. These are used at power stations, as without them, there would not be enough power to transport the electricity around the national grid.
Hope this helps :)

7 0

3 years ago

Read 2 more answers

If a car starts at rest and accelerates at 3.4 m/s^2 over a distance of 200 meters, how fast will it be travelling at the end?

CaHeK987 [17]

Answer:

36.9 m/s

Explanation:

From;

v^2 = u^2 + 2as

Where;

v = final velocity =?

a = acceleration = 3.4 m/s^2

u = initial velocity = 0 m/s

s = distance covered = 200 meters

v^2 = 0^2 + 2 * 3.4 * 200

v^2 = 1360

v = √1360

v = 36.9 m/s

8 0

3 years ago