Answer:
Data supports significantly because we can use the testing(depending sample) before and after we use the same object to test the hypothesis.
Answer:
Kinetic energy: 
Velocity: 
Explanation:
From the equations of the photo-electric effect,
We know:
Where,
1.
is the Planck's constant which is 
2.
are the frequency of light emitted and threshold frequencies respectively.
3.
is the kinetic energy of the electrons emitted.
By fact, we come to know that the threshold frequency of Zn is 300nm
And also 
Where ,
1. 
is the speed of light 
2.
is the wavelength.
Thus,
Now to find velocity:
The two reasons why the UK government is
encouraging citizens to recycle iron and steel is:
<span><span>
1. </span>The environment. Every machinery and device the industries makes
which includes, infrastructures, mega structures to micro devices. Iron and
steel is used. Reducing the extraction of ore and creating steel saves the
environment, reduces mining.</span>
<span><span>
2. </span>Economic reasons. When the ore mining and steel making is reduced
in activity, the government won’t just be able to save the environment but it
also save funds for other purposes.</span>
The correct answer is actually
D. requires a lot of energy to become hot.
As the definition of specific heat is "the heat required to raise the temperature of the unit mass of a given substance by a given amount."
