What are the noise control methods? Extraction, ventilation, cooling, openings in walls and enclosures. Instead of fitting silencers, it is often possible to achieve a 10 – 20 dB reduction in airborne noise from a duct or opening by lining the last bend in the ductwork with acoustic absorbent (foam or rockwool / fibreglass). Which […]
What did Penzias and Wilson discovery prove?
What did Penzias and Wilson discovery prove? Penzias and Wilson had spotted the CMB, the predicted thermal echo of the universe’s explosive birth. The landmark find put the Big Bang theory on solid ground, suggesting that the cosmos did indeed grow from a tiny seed — a single point — about 13.8 billion years ago. […]
What is the best sampling method?
What is the best sampling method? Random sampling What are the 4 types of sampling? There are four main types of probability sample. Simple random sampling. In a simple random sample, every member of the population has an equal chance of being selected. Systematic sampling. Stratified sampling. Cluster sampling. What are the sampling methods? Methods […]
What is an ionic bond write two examples?
What is an ionic bond write two examples? An ionic bond is formed as a result of the electrostatic attraction between the positive and negative ions formed by the transfer of electrons from one atom/group to another. Examples: NaCl,KBr,etc. What is ionic and covalent bond explain with example? The two main types of chemical bonds […]
Why is the maximum possible heat rate for a heat exchanger not equal to Cmax Thi TCI?
Why is the maximum possible heat rate for a heat exchanger not equal to Cmax Thi TCI? Why is the maximum possible heat rate for a heat exchanger not equal to Cmax(Thi-Tci)? Can the outlet temperature of the cold fluid ever exceed the inlet temperature of the hot fluid? No the outlet temperature of the […]
How do gamma rays work?
How do gamma rays work? Gamma-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. These waves are generated by radioactive atoms and in nuclear explosions. Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells. Why are gamma […]
What are the 10 principles of community policing?
What are the 10 principles of community policing? Philosophy and organisational strategy. Commitment to community empowerment. Decentralised and personalised policing. Immediate and long-term proactive problem solving. Ethics, legality, responsibility and trust. Expanding the police mandate. Helping those with special needs. Grass-roots creativity and support. Does community based policing work? There is research to demonstrate that […]
What are 2 parts of transverse wave?
What is a dumb question?
What is a dumb question? Dumb questions are simple questions that probe the obvious, and simultaneously challenge and direct our thinking. Dumb questions are not accusatory or argumentative statements in disguise. Nor are they formulated with preconceived answers in mind. Rather, they are probing yet open. What is the world’s stupidest question? The 30 Dumbest […]
What is the closest thing to pure energy?
What is the closest thing to pure energy? Light What is the purest form of energy? Unlike any other living thing on Earth, electric bacteria use energy in its purest form – naked electricity in the shape of electrons harvested from rocks and metals. What are pure energy beings? An energy being or astral being […]