Question # 13.1
Electron leave
the fry cell and flow through a lamp bulb back to the cell. Which terminal, the
positive or negative or the negative is the one from which electrons leave the
cell? In which direction is the conventional current?
Ans: Electrons
leave the cell from the negative (-ve) terminal pass the through the bulb go to
the positive (+ve) terminal of the cell.
HEAT
In 18th and beginning of 19th century heat was considered was
weight less fluid according to the caloric theory the hot body contains more
caloric then the cold bodies.
Count Rumford Challenge on Caloric concept
In 1798 count Rumford (Benjamin) challenge the concept heat fluid.
Count Rumford concluded that the heat is produced by friction while is caused
by friction.
James
Joules Experiment On Heat
1840 James Joule support the theory of Count Rumford that:
Ø
Heat is not as the flow of substance
(calorie).
Ø
Heat is the form of energy flow from
hot body to cold body.
Ø
Heat is the form of energy that
transfer body because of temperature’s difference.
Definition
“Heat is the
sum of kinetic energy of all molecules or atoms of body system.”
Once the heat is transferred into body it will converted internal
energy.
According to the kinetic theory of the molecule. The Molecules of
the body always be in motion. The motion of the molecule is due to the kinetic
energy which possessed by the molecule.
Then the sum of
the kinetic energy of all the molecules is called “Heat”.
INTERNAL ENERGY
ANOMALOUS EXPANSION OF WATER
Most of the liquids expands on heating while contract on cooling. However, water at 0oC when heated, starts contracting on heating instead of expanding. After 4oC it starts expanding on heating normally like other liquids. It is also seen that hot water when cooled up to 4oC and its density increases.
However, further on from 4oC to 0oC it expands. At 0 oC the water changes in to ice. Due to expansion, the density of it at 0 oC becomes less than water so ice floats on water. At 0 oC water has maximum density and least volume. This is called anomalous or irregular behavior behavior of water.
Effect of Anomalous Expansion of Water.
In colder climate, when the atmospheric temperature starts falling. The density of water in seas and lakes starts to rise reaching to maximum at 4 degree Celsius. This heavier water at 4 degree Celsius goes to lower depths and replace by warmer water. The process goes on till all the water in the lakes acquires a uniform temperature if 4 degree Celsius. if the atmospheric temperature continues falling below 4 degree Celsius, the water starts expanding and begin lighter it does not sink down. At reaching 4 degree Celsius , waters freezes on the surface but the water below the ice remain at 4 degree Celsius. Since ice a bad conductor of heat, it does not allows the heat contained in water below to escape into the atmosphere through the ice sheet. As a result even in the coldest season, the water at lower depths remain in liquid form, providing life to aquatic animals.
Albert Einstein
Albert Einstein
Born: fourteen March 1879
Died: eighteen April 1955
He was a German theoretical scientist.
He developed the idea of relativity theory that is one pillar of trendy physics.
He is best celebrated to the overall public for his mass relation E = mc2,.
He awarded the award in Physics in 1921 on the discovery of the law of the photoelectrical impact.
He was the son of a salesperson United Nations agency later operated Associate in Nursing chemistry plant.
Albert Einstein received unearned doctor's degree degrees in science, drugs and philosophy from several European and yankee universities
DR. ABDUL SALAM
Dr. Abdul Salam was in 1926 in Jhang (Punjab). He always got distinction in his exams. He was awarded a scholarship for higher studies in the United Kingdom. His Contributions are as under:
He Proposed Grand unification theory (GUT). He combined two basic forces, that is the weak nuclear force is solved in a single mathematics equation.
He established International center of Theoretical physics, at Trieste, Italy. There are scientists who came from developing countries and are given opportunities to increase their research work with elites of physics.
He got Nobel Prize in Physics in 1979 along with two other scientists for his work on grand unification theory.
DR. ABDUL QADEER KHAN
 |
| Dr. Abdul Qadeer Khan |
Dr. AQ Khan was born in 1936 in Bhopal in city if India. He Got his M.Sc. degree in metallurgy from the university of in Holland.
He selected as research assistant in the same university(HOLLAND). He got a PhD degree from the University of Leaven, Belgium. His contributions are given as under:
He worked as an expert at Urenco enrichment plant in Holland.
It was all due to his efforts that Pakistan became a nuclear state.
He managed the setup to build the atomic bomb.
He trained the scientists in the nuclear field.
He served as the director of Kahuta Nuclear research laboratories, which is now called A.Q. Khan research laboratories.
He made Pakistan strong by and strategies in his work.
Dr. Abdul Qadeer Khan is a true Patriotic Person. He came to Pakistan to serve his country. The government of Pakistan has awarded him Hilal-I-Imtiaz for his services to the country.
Important Note: This information is beneficial for HSC SSC and other students.
Particles Found to Travel Faster Than Speed of Light
Neutrinos called ghostly subatomic particles, may have been observed traveling faster than the speed of light.
An Italian experiment has give evidence that nutrinos which are called fundamental particles can travel faster than light. The experiment is called OPERA (Oscillation Project with Emulsion_tRacking Apparatus) and lies 1400 m underground in the Gran Sasso National Lab in Italy. It is designed to study a beam of neutrinos coming from CERN, Europe's premier high-energy physics laboratory located 730 km away near Geneva, Switzerland. Neutrinos are fundamental particles that are electrically neutral, rarely interact with other matter, and have a negligible small mass. But they are all around us, the sun produces so many neutrinos as a result of nuclear reactions that many billions pass through your eye every second.
