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sdas [7]
3 years ago
11

I need to know which ones are physical or chemical changes.

Physics
1 answer:
andrezito [222]3 years ago
7 0
Physical
Chemical
Physical
Chemical
Chemical
Chemical
Physical
Physical
Physical
Chemical
Chemical
Physical
Physical
Physical
Chemical
Chemical
Chemical
Chemical
Physical
Chemical
Chemical
Chemical
Chemical
Chemical
Chemical

I believe this is right but double check to make sure :)
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6. If two objects each have a mass of 10 kg, then the force of gravity between them
frozen [14]

Answer:

3

Explanation:

Answer is what its supposed to be. lol.

Stick with it brother. You GOT THIS!!! 100%

b.

8 0
2 years ago
Recall from Chapter 1 that a watt is a unit of en- ergy per unit time, and one watt (W) is equal to one joule per second ( J·s–1
harkovskaia [24]

Answer:

Explanation:

The energy of a photon is given by the equation E_p=h f, where h is the <em>Planck constant</em> and f the frequency of the photon. Thus, N photons of frequency f will give an energy of E_N=N h f.

We also know that frequency and wavelength are related by f=\frac{c}{\lambda}, so we have E_N=\frac{N h c}{\lambda}, where c is the <em>speed of light</em>.

We will want the number of photons, so we can write

N=\frac{\lambda E_N}{h c}

We need to know then how much energy do we have to calculate N. The equation of power is P=E/t, so for the power we have and considering 1 second we can calculate the total energy, and then only consider the 4% of it which will produce light, or better said, the N photons, which means it will be E_N.

Putting this paragraph in equations:

E_N=(\frac{4}{100})E=0.04Pt=(0.04)(100W)(1s)=4J.

And then we can substitute everything in our equation for number of photons, in S.I. and getting the values of constants from tables:

N=\frac{\lambda E_N}{h c}=\frac{(520 \times10^{-9}m) (4J)}{(6.626\times10^{-34}Js) (299792458m/s)}=1.047 \times10^{19}

3 0
3 years ago
A scientist notices that an oil slick floating on water when viewed from above has many different colors reflecting off the surf
Sati [7]

Answer:

a) The minimum thickness of the oil slick at the spot is 313 nm

b) the minimum thickness be now will be 125 nm

Explanation:  

Given the data in the question;

a) The index of refraction of the oil is 1.20. What is the minimum thickness of the oil slick at that spot?

t_{min = λ/2n

given that; wavelength λ = 750 nm and  index of refraction of the oil n = 1.20

we substitute

t_{min = 750 / 2(1.20)

t_{min = 750 / 2.4

t_{min = 312.5 ≈ 313 nm

Therefore, The minimum thickness of the oil slick at the spot is 313 nm

b)

Suppose the oil had an index of refraction of 1.50. What would the minimum thickness be now?

minimum thickness of the oil slick at the spot will be;

t_{min = λ/4n

given that; wavelength λ = 750 nm and  index of refraction of the oil n = 1.50

we substitute

t_{min = 750 / 4(1.50)

t_{min = 750 / 6

t_{min = 125 nm

Therefore, the minimum thickness be now will be 125 nm

4 0
3 years ago
What must be true about a surface in order for diffuse reflection to occur?
balu736 [363]

Answer:

carpet

Explanation:

Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection.

The structure of carpet's surface is as shown. Thus it shows large amount of diffuse reflection.

4 0
3 years ago
Can there be displacement of an object in the absence of any force acting on it? Think, Discuss it with your friends and teacher
Fudgin [204]

Answer:

An object can have a displacement in the absence of any external force acting on it

Explanation:

When a object moves with a constant velocity (v), then it gets displaced in the direction of motion but the net external force experienced by the object is zero.

F  external  =ma

If object moves with constant velocity, acceleration is zero.

Since, a=0  ⟹F  external  =0

Using  s=ut+  1/2 at  ^2

 ⟹    Displacement    s=ut    (∵a=0)

Hence, an object can have a displacement in the absence of any external force acting on it

Hope this helped you:)

5 0
3 years ago
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