Answer:
Zero
Explanation:
It is given that,
A person swims to the other end of a 20m long pool and back.
We need to find his displacement.
Displacement = shortest path covered
He reaches at the same position as from where he has started. It means the shortest path covered is equal to 0 i.e. his displacement is zero.
Answer:
B. Convection
D. Conduction
Explanation:
Conduction and convection are the two most prominent processes that helps transfer energy outward to the earth's crust.
- Energy within the core is a function of the radioactive decay and frictional heating.
- Also, heat that accreted during the formation of the earth is a significant source of internal energy.
- The heat is conducted away by the process of convection. This is possible due to temperature differences between different parts of the earth
- Conduction is made made possible due to the metallic bodies in the core and other part of the inner earth.
Answer: True
Explanation:
Atomic number is defined as the number of protons or the number of electrons that are present in an electrically neutral atom.
Atomic number = Number of protons = number of electrons = 2
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electronic configuration will be 
As its duplet is already complete and it has noble gas configuration , it is stable with 2 valence electrons.
Efficiency = (energy that does the job) / (total energy used)
= (45 J) / (120J)
I think you can handle the division.