D) Radioactive contamination
Answer:
1, just I) color.
Explanation:
Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point.
A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling.
Chemical properties are the properties that need a reaction to being observed, such as the combustibility, which needs a combustion reaction to being quantified.
When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.
So, the heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.
Electrons are emitted from the surface of a metal in photoelectric effect.
<h3>What is the photoelectric effect?</h3>
The photoelectric effect is the emission of electron from the surface of a metal when light is shone on the surface..
For electrons to be emitted, the light must have a certain frequency known as threshhold frequency.
Therefore, electrons are emitted from the surface of a metal in photoelectric effect.
Learn more about photoelectric effect at: brainly.com/question/21320305
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<em>Answer:</em>
4) the one that is reduced, which is the oxidizing agent
<em>Explanation:</em>
<em>An oxidizing agent is one that causes oxidation by gaining electrons from another atom/molecule. </em>
