Answer: Option (D) is the correct answer.
Explanation:
Need means necessity without which a person might not be able to survive for long.
For example, food is a need for every living being as without it any individual cannot survive for a long period of time.
Similraly, shelter is also a need and insurance is also necessary as it protects an individuals life or his savings so that after his death the future of his family remains protected.
Whereas cable TV is not a need as an individual can survive without it. Therefore, a cable TV is a want.
Answer:
KBr dissolved in water.
Explanation:
A substance conducts electricity as a result of the presence of mobile ions in the substance.
An ionic substance such as KBr when dissolved in water releases free ions which become charge carriers in solution hence the solution conducts electricity. Solid ionic substances such as solid KBr and solid baking soda do not conduct electricity because the ions are strongly bound to each other in the crystal lattice.
Molecular substances such as sugar and alcohol do not conduct electricity even in solution.
Answer:
bonds within the nucleus of reactants atoms are broken and rearranged to form new product atoms
Answer:
the volume of the sound will quarter
Explanation:
As you move far away from the source, the loudness of sound decreases. This is because as the distance from the source increases, the area it covers also increases thereby spreading the energy over a great area leading to lesser loudness and intensity.
As a result of this, sound intensity follows an inverse square law:
I ∝ 1/d²; where I is the intensity and d is the distance from source.
Therefore If a speaker is moved from 2 feet away to 4 feet away (increment of 2 feet), the volume of the sound would quarter (1/2² = 1/4)
