Answer:
John Dalton:
John Dalton was the scientist who introduced atomic theory in the field of chemistry. Dalton worked on different gases and formulated this theory. The main points of Dalton's theory are:
- Every element present is made up of atoms.
- Atoms of an elements are have the same same properties whereas these properties are different for each element.
- According to his theory, an atom could not be broken down.
- Different atoms combine or get separated from each other during a chemical reaction.
Ernest Rutherford:
Ernest Rutherford is known as the father of nuclear physics due to his impressing research work on radioactivity of atoms. Rutherford was the first scientist to discover the nucleus of an atom and prove that the nucleus was charged. He also described that the electrons circle around the nucleus of an atom.
The right option is; b. mechanical
Mechanical energy is the best description of the energy of the ball as it flies over the pitcher’s head.
Mechanical energy is the energy that an object acquires due to its position or due to its motion. From the question, the baseball player has chemical potential energy (stored as food) which is transformed into work. As the baseball player hits the ball, there is energy exchange in which the ball acquires energy to perform its work. The energy obtained by the ball upon which work is done is called mechanical energy.
J. J. Thomson discovered electron by performing an experiment using cathode ray tubes. High voltage across is applied across two electrodes at that causes a beam of particles to flow from the the negatively-charged electrode that is cathode to the positively-charged electrode that is anode. Properties of the particles, are tested using two oppositely-charged electric plates around the cathode ray. The cathode ray was deflected away from the negatively-charged electric plate and towards the positively-charged plate. This indicated that the cathode ray was composed of negatively-charged particles. And these negatively charged particles are called electrons.
the element hydrogen atom is made up of oxygen atoms.
