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4 years ago

Which variable stars have pulsation periods between 1.5 hours and 1.2 days?

2 answers:

7 0

D. Nebulas is a cloud of dust,
B. Protostars & A. Cepheid variables have longer pulsation periods.
Whereas, C. RR Lyrae variables have pulsation periods between 1.5 hours and 1.2 days. So the answer is C.

maria [59]4 years ago

3 0

Correct answer choice is :

C) RR Lyrae variables

Explanation:

RR Lyrae variables are periodical unsteady stars, usually discovered in globular groups. They are accepted as regular lights to measure galactic distances, as a part of the infinite distance ladder. This class of unsteady star is identified after the prototype and glorious example, RR Lyrae. R Lyraes are vibrating parallel section aging stars of phantom class A or F, with a mass of around half the Sun's.

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which of the folloing statements about ionization energy is true? A elements toward the bottom of a group periodic table general

beks73 [17]

<span>
accept the flow of electrons.resist the flow of electrons.accept the flow of protons.resist the flow of protons.It is one of these </span>

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3 years ago

A current-carrying wire oriented north-south and laid over a compass deflects the compass 8° to the east. What is the magnitude

zhenek [66]

$2.8 \times 10^{-6}\ T$ is the magnitude of the magnetic field made by the current

<u>Explanation:</u>

Given data:

$\theta=8^{\circ}$

Magnetic field of earth, $B_{\text {earth}}=2 \times 10^{-5}\ \text {tesla}$

We need to find the magnetic field of wire, $B_{\text {wire }}$

The compass needle moves toward a direction of magnetic field. The current in wire makes a magnetic field in available space where the compass is on the ground. The vector sum of the Earth's magnetic field and the wire's magnetic field represents the net magnetic field, as shown in the attached drawing, expressing the angle:

$\tan \theta=\frac{B_{\text {wire}}}{B_{\text {earth}}}$

By substituting the given values, we get

$B_{\text {wire}}=\tan \theta \times B_{\text {earth}}=\tan 8^{\circ} \times 2 \times 10^{-5}=0.1405 \times 2 \times 10^{-5}$

$B_{\text {wire}}=0.28 \times 10^{-5}=2.8 \times 10^{-6}\ T$

4 0

3 years ago

A volumetric flask made of Pyrex is calibrated at 20.0°C. It is filled to the 150-mL mark with 34.5°C acetone. After the flask i

8_murik_8 [283]

Answer:149.73 ml

Explanation:

Given

$\beta \ of\ acetone=1.50\times 10^{-4} ^{\circ}C^{-1}$

change in volume is given by

$\Delta V=V_{final}-V_{initial}$

$\Delta V=\nu_{initial}\beta _{acetone}\left [ T_f-T_i\right ]$

$V_{final}=\nu_{initial}+\nu_{initial}\beta _{acetone}\left [ T_f-T_i\right ]$

$V_{final}=150+150\times 1.50\times 10^{-4}\left [ 20-32\right ]$

$V_{final}=149.73 ml$

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4 years ago

A gas expands at a constant pressure of 3 atm from a volume of 0.02 cubic meters to 0.10 cubic meters. In the process it experie

Nonamiya [84]

a) $2.4\cdot 10^4 J$

For a gas transformation occuring at a constant pressure, the work done by the gas is given by

$W=p(V_f -V_i)$

where

p is the gas pressure

V_f is the final volume of the gas

V_i is the initial volume

For the gas in the problem,

$p=3 atm = 3\cdot 1.013\cdot 10^5 Pa = 3.039\cdot 10^5 Pa$ is the pressure

$V_i = 0.02 m^2$ is the initial volume

$V_f = 0.10 m^3$ is the final volume

Substituting,

$W=(3.039\cdot 10^5 Pa)(0.10 m^3-0.02m^2)=24312 J = 2.4\cdot 10^4 J$

b) $3.24\cdot 10^5 J$

The heat absorbed by the gas can be found by using the 1st law of thermodynamics:

$\Delta U = Q-W$

where

$\Delta U$ is the change in internal energy of the gas

Q is the heat absorbed

W is the work done

Here we have

$\Delta U = 3.0\cdot 10^5 J$

$W=2.4\cdot 10^4 J$

So we can solve the equation to find Q:

$Q=\Delta U + W = 3.0\cdot 10^5 J +2.4\cdot 10^4 J = 3.24\cdot 10^5 J$

And this process is an isobaric process (=at constant pressure).

8 0

3 years ago

Suppose a drinking straw is in a glass of water. Someone blows air across the top of the straw. The water level in the straw ___

enyata [817]

The answer is A. drops! Suppose a drinking straw is in a glass of water. Someone blows air across the top of the straw. The water level in the straw will be drops.

Hope it helped!

7 0

4 years ago

Read 2 more answers