Answer:
c
Explanation:
b and d are out, the variables are changed. a would be a repetition, not a replication. c uses the same method and variables with a different control group
Explanation:
Tc - 99 is technetium 99.
It is a radioactive element that decays spontaneously. It has a half-life of 211,000 years and decays to stable ruthenium.
- On the periodic table, it has an atomic number of 43;
Mass number = 99
Atomic number = number of protons = number of electrons in atom
Number of protons in Tc is 43
electron is 43
Mass number = number of protons + number of neutrons
Number of neutrons = mass number - number of protons = 99-43 = 56
learn more:
Atomic number brainly.com/question/2057656
#learnwithBrainly
Answer:
The percentage efficiency of the electrical element is approximately 82.186%
Explanation:
The given parameters are;
The thermal energy provided by the stove element, 
= 3.34 × 10³ J
The amount thermal energy gained by the kettle, 
= 5.95 × 10² J
The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;
Therefore, we get;
The percentage efficiency of the electrical element, η% ≈ 82.186%.
The flotation process used in metallurgy involves the separation of gangue from ore.
<h3>How does the flotation process work?</h3>
The various wettability qualities of a material's surface are the foundation of flotation operations. The basic principles of flotation are quite similar to those of a sink and float process, where the materials' relative densities to the medium in which they are deposited determine the basis of the separation.
<h3>What is the process of separating minerals from gangue known as?</h3>
Mineral processing, mineral dressing, or ore dressing are all terms for the process of separating minerals from gangue. It is an important and frequently necessary part of mining. Depending on the type of minerals used, the process may be difficult.
Learn more about minerals here:-
brainly.com/question/26705337
#SPJ4
