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3 years ago

1. How are science and technology related? (1 point)

Physics

1 answer:

alina1380 [7]3 years ago

8 0

Answer:

Explanation:

1.Technology is an application of science through use of modern scientific tools.

2.They provide a concrete view of something abstract. They are also applicable to gain an understanding of better process and systems.

3.C.55.25s

4. A. straight line graph.

5. A. Milk. A pure substance consist of a single element or compound.

6.B. it has two hydrogen atom to one oxygen atom

7.B. Sugar water.

8.D.Size of their particles.

9.A.sawing a piece of wood into half.

10.A..iron changes colour when heated.

11.A.solid

12.A. Lowering the temperature, which lead to increase in gas volume according to. Boyle's law.

13.C. boiling point of naphthalene.

14.freezing,which is the mostly orderly point of water because water moves from liquid to solid state.

15.A.sublimation.

16.B.Vaporisation.

17.C.it is described by a nucleus surrounded by a large volume is space.

18. The atom in the excited state has more energy and is less stable than atom in the ground state.

19.The discovery of elements with predicted properties.

20.The sum total of mass of an element.

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The Law of Conservation of Mass states that mass can be destroyed during a chemical change.

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The law of conservation of mass states that mass can be destroyed during a chemical change is TRUE

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3 years ago

The following table lists the work functions of a few commonmetals, measured in electron volts.

steposvetlana [31]

Answer:

Lithium

Explanation:

The equation for the photoelectric effect is

$\frac{hc}{\lambda}= \phi + K_{max}$

where

$\frac{hc}{\lambda}$ is the energy of the incident photon, with

h being the Planck constant

c is the speed of light

$\lambda$ is the wavelength of the photon

$\phi$ is the work function of the metal (the minimum energy needed to extract the photoelectron from the metal)

$K_{max}$ is the maximum kinetic energy of the emitted photoelectrons

In this problem, we have

$\lambda= 190 nm = 1.9\cdot 10^{-7}m$ is the wavelength of the incident photon

$K_{max}=4.0 eV$ is the maximum kinetic energy of the electrons

First of all we can find the energy of the incident photon

$E=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{1.90\cdot 10^{-7} m}=1.05\cdot 10^{-18} J$

Converting into electronvolts,

$E=\frac{1.05\cdot 10^{-18} J}{1.6\cdot 10^{-19} J/eV}=6.6 eV$

So now we can re-arrange the equation of the photoelectric effect to find the work function of the metal

$\phi = E-K_{max}=6.6 eV - 4.0 eV=2.6 eV$

So the metal is most likely Lithium, which has a work function of 2.5 eV.

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3 years ago

A 6.5 l sample of nitrogen at 25◦c and 1.5 atm is allowed to expand to 13.0 l. the temperature remains constant. what is the fin

ollegr [7]

Since the temperature of the gas remains constant in the process, we can use Boyle's law, which states that for a gas transformation at constant temperature, the product between the gas pressure and its volume is constant:
$pV=k$
which can also be rewritten as
$p_1 V_1 = p_2 V_2$ (1)
where the labels 1 and 2 mark the initial and final conditions of the gas.

In our problem, $p_1 = 1.5 atm$ , $V_1 =6.5 L$ and $V_2 =13.0 L$ , so the final pressure of the gas can be found by re-arranging eq.(1):
$p_2 = p_1 \frac{V_1}{V_2}= (1.5 atm) \frac{6.5 L}{13.0 L}=0.75 atm$

Therefore the correct answer is
<span>1. 0.75 atm</span>

8 0

3 years ago

What is the gravitational acceleration close to the surface of a planet with a mass of 9ME and radius of 3RE, where ME and RE ar

Papessa [141]

Answer:

9.78 m/s²

Explanation:

To solve this, we use the gravitational formula

g = GM/r², where

g = acceleration due to gravity

G = gravitational constant

M = mass of the planet

r = radius of the planet

From the question, we got that the mass of the planet is

M = 9ME, where ME = 5.95*10^24

M = 9 * 5.95*10^24

M = 5.355*10^25 kg

Also, the Radius of the planet, R = 3RE, where RE = 6.37*10^6

R = 3 * 6.37*10^6

R = 1.911*10^7 m

On applying the values of both R and M to the equation, we get

g = GM/r²

g = (6.67*10^-11 * 5.355*10^25) / (1.911*10^7)²

g = 3.57*10^15/3.65*10^14

g = 9.78 m/s²

Therefore, the acceleration due to gravity on the planet is 9.78 m/s²

Please vote brainliest if it helped you <3

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3 years ago

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nydimaria [60]

Answer: If there is a higher friction, the opposition force is higher so that it can reduce our speed. So, a factor that affects friction is the roughness or smoothness of the surface of the object. In comparison of the table with the fabric, the fabric will have a more opposition force. As the surface of the fabric is usually rougher than the surface of a smooth table. As there is more friction on a fabric, we will feel more opposition force on our finger tip.

Hope it helped! :>

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3 years ago