Answer: To isolate the unknown substances, of which only tiny amounts were present, the Curies were the first to use a new method of chemical analysis. They employed various standard (but sometimes demanding) chemical procedures to separate the different substances in pitchblende.
Explanation:
Answer:
Lower energy shell which will be nearer to the nucleus.
Explanation:
When electron move from one energy level to another, an electron must gain or lose just the right amount of energy.
When atoms releases energy, electrons move into lower energy levels. The electrons in the shells aways from the nucleus have more energy as compared to the electrons in the nearer shells.
Electrons with the lowest energy are found closest to the nucleus, where the attractive force of the positively charged nucleus is the greatest. Electrons that have higher energy are found further away
Answer: <em>Option (A) is correct.</em>
Explanation:
A heuristic is often referred to as an approach to solving problems or discovery that subjects a method, which is considered to be practical although might not be guaranteed to be perfect, optimal, or rational, but sufficient for reaching to goal.
Empiricism is known as a theory under which one can states that knowledge can only be imparted from the sensory experience. It is considered to be one of the main notions underlying in epistemology, i.e. known as the study of human knowledge, alongside skepticism and rationalism.
Answer:
Position at t= 4 seconds is 144 m
Explanation:
It is given that acceleration, a = 18 t, where t is the time.
We know that Velocity, 
Substituting value of a,
Velocity, 
We know that at t = 0, v = -12 m/s
So, 
So velocity, 
We also know that displacement, 
Substituting value of v,
Displacement, 
We know that at t = 0, particle is at origin, x =0.
So, 
Displacement, 
At t = 4 seconds
Position at t= 4 seconds is 144 m
