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3 years ago

An observation of the red shift of galaxies suggestst that the universe is

1 answer:

3 0

A) Expanding. We know this because it has a similar effect with sound. When a car goes by the pitch gets deeper and deeper. It's because you're receiving less waves. Same thing for light but instead of a pitch it's light, and the farther spread the waves - the redder, the closer and more contracted - the bluer

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Two wires are made from the same material. One wire has a resistance of 0.10 ω. The other wire is twice as long as the first wir

Anna71 [15]

Answer:

Explanation:

Given that,

First wire has a resistance of

R1 = 0.1 Ω

We are told that

Second wire is twice as long as the first wire.

Then,

Let the first wire has length

L1 = x

Then, second wire will have

L2 = 2x

Also, the radius of the second wire is half the radius of the first wire

Let the first wire has radius

r1 = y

Then, it area is

A1 = πr1² = πy²

Then, the second wire has radius

r2 = ½y

It area is also

A2 = πr2² = π(½y)² = ½πy²

Since the wire is made of the same material, then, they will have the same resistivity ρ

Then, we want to find the resistance of the second wire

Using

R = ρL/A

Where

R = resistance

ρ = sensitivity

L = length

A = area

Then, make resistivity subject of formula since it is a constant

RA = ρL

Then, ρ = RA/L

Then,

R1 • A1 / L1 = R2 • A2 / L2

Substituting each value

0.1 × πy² / x = R2 × ¼πy² / 2x

Cross multiply

0.1 × πy² × 2x = R2 ×¼π y² × x

Then,

R2 = 0.1 × πy² × 2x / ¼πy² × x

R2 = 0.1 × 2 / ¼

R2 = 0.8Ω

The resistance of the second wire is 0.8Ω

6 0

4 years ago

What are the three most important types of units in radiobiology? Explain the meaning of each.

Rom4ik [11]

Answer:

Most adverse health effects of radiation exposure may be grouped in two general categories:

deterministic effects (harmful tissue reactions) due in large part to the killing/ malfunction of cells following high doses; and

stochastic effects, i.e., cancer and heritable effects involving either cancer development in exposed individuals owing to mutation of somatic cells or heritable disease in their offspring owing to mutation of reproductive (germ)

4 0

3 years ago

Calculate the pressure, in atmospheres, exerted by each of the following:

gregori [183]

Answer:

a) 14.2 atm

b) 4.46 atm

c) 1.06 atm

Explanation:

For an ideal gas,

PV = nRT

P = pressure of the gas

V = volume occupied by the gas

n = number of moles of the gas

R = molar gas constant = 0.08206 L.atm/mol.K

T = temperature of the gas in Kelvin

a) For HF,

P =?, V = 2.5L, n = 1.35 moles, T = 320K

P = 1.35 × 0.08206 × 320/2.5

P = 14.2 atm

b) For NO₂

P =?, V = 4.75L, n = 0.86 moles, T = 300K

P = 0.86 × 0.08206 × 300/4.75

P = 4.46 atm

c) For CO₂

P =?, V = 5.5 × 10⁴ mL = 55L, n = 2.15 moles, T = 57°C = 330K

P = 2.15 × 0.08206 × 330/55

P = 1.06 atm

4 0

4 years ago

The geologic force applied to rocks is called

amid [387]

The geologic force applied to rocks is called compression. Compression is the stress that squeezes rocks together. As a result of the compression rocks fold or fracture depending on their compressive strength or compression strength - the capacity of a material or structure to withstand loads tending to reduce size.
When the compression is horizontal the crust will be shortened and thickened. When the compression is vertical maximum a section of rock will fail in normal faults, horizontally extending and vertically thinning a given layer of rock.

4 0

3 years ago

Which statement describes a controlled experiment?

olga_2 [115]

Answer:

In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. The researcher can operationalize (i.e. define) the variables being studied so they can be objectivity measured.

7 0

4 years ago