The question asks for the meaning of the Greek word 'a-tomio' from which the word 'atom' is derived. We need to recall the historical context of the atomic theory and the etymology of the word 'atom'.
Correct Option: C) Both a and b
The word 'atom' is derived from the Greek word 'a-tomio' (or 'atomos'), which means 'non-divisible' or 'uncuttable'. Both terms accurately describe the original philosophical concept of an atom as the fundamental, indivisible particle of matter.
The question asks to identify the scientist who first proposed the atomic theory of matter on a firm scientific basis. This requires knowledge of the history of atomic theory and the contributions of key scientists.
B) John Dalton proposed the first comprehensive atomic theory of matter on a firm scientific basis in the early 19th century. His theory was based on experimental evidence and explained the laws of chemical combination.
This question tests fundamental knowledge of electrostatics, specifically the interaction between charged particles. The basic principle is that like charges repel, and unlike charges attract.
A) Attract β This is the correct term to describe the interaction between unlike electric charges. Positive and negative charges are drawn towards each other.
The question asks to identify a substance synthesized in the human body that causes blood vessel dilation and increased blood flow. This points to a molecule with a specific physiological role in the cardiovascular system.
A) Nitric oxide is a crucial signaling molecule in the cardiovascular system. It is produced by endothelial cells and acts as a powerful vasodilator, relaxing the smooth muscles of blood vessels. This relaxation leads to the widening of blood vessels (dilation) and a subsequent increase in blood flow, which helps regulate blood pressure and deliver oxygen and nutrients to tissues.
The question asks about the charge of a cathode. To answer this, we need to understand the fundamental definitions of electrodes in electrochemical cells (both electrolytic and galvanic).
Correct Option: D) Negative. The cathode is the electrode that attracts positive ions (cations) and where reduction (gain of electrons) occurs. To attract positive ions, the cathode must be negatively charged.
The question asks to identify the scientist responsible for demonstrating that passing electricity through an electrolyte solution causes chemical reactions at the electrodes, leading to the liberation or deposition of matter. This phenomenon is known as electrolysis.
B) Michael Faraday β Michael Faraday (1791-1867) conducted extensive research on the effects of electric current on chemical solutions. He established that when electricity is passed through an electrolyte, chemical changes occur at the electrodes, leading to the decomposition of the electrolyte and the deposition or liberation of matter. His two laws of electrolysis are foundational to electrochemistry.