Physical Quantity: Any measurable quantity is called Physical Quantity.
Base Quantity: The physical quantity that could be measured independently is called a base quantity.
I will be removing the phrase .........is called or ........is defined as ...
Derived Quantity: The physical quantity that depends upon other physical quantities for measurement.
Vector: The physical quantity that has both magnitude and direction.
Scalar: The physical quantity that has magnitude only.
Actually, vector means 'to carry' and scalar means 'of a scale', so if we try to learn through etymology we can learn the definitions easily.
Precision: The degree to which the observed values are least scattered.
The precision is the measure of goodness of data. Many of us may have misconception that precision has to do anything with the errors made by experimenter. During recording of data, we take a large number of data. Precision refers to the spread of data for at least one fixed parameter.
Accuracy: The degree to which the observed value approaches the true value.
The accuracy is based on the type of instrument we use. If a length is measured with a micrometer screw gauze the reading may be 1.738 cm, the same length recorded by vernier calipers is 1.74 cm and for meter rule it is 1.7 cm. Here the degree of accuracy is decreasing. Actually, the least count plays an important role on accuracy of the data.
Systematic Error: The error that arises due to known causes.
As the cause is known one can eliminate the error by proper adjustment of the instrument. Furthermore, if the reading has a error of same magnitude, it is a systematic error.
Random Error: The error that arises due to unknown causes.
As the cause is unknown, it can't be removed; but one can minimize the error by taking multiple readings for a parameter and taking the average value.
Though Quantum Mechanics is very interesting we find it difficult during our examinations. I have tried to solve the questions of Quantum Mechanics and Radioactivity of GCE A Levels( 9702). Click the link Solved Paper of Quantum Mechanics 9702 to download the solved paper.
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Sunlight exerts pressure (solar radiation pressure).
On average, our bodies constantly resist an atmospheric pressure of about 1kg per square cm. Thanks to blood pressure otherwise I wouldn't have been writing this.
Due to the effect of Thermal Expansion, the Eiffel Tower is upto 15cm taller in summer.
If an atom were the size of a stadium, its electrons would be as small as bees. Comparable dimensions!!
If given the same mass, our body would actually be hotter than the Sun. The continuous conversion of chemical energy to thermal energy.
The only rock that floats in water is pumice. Its an igneous rock.
On average, our bodies constantly resist an atmospheric pressure of about 1kg per square cm. Thanks to blood pressure otherwise I wouldn't have been writing this.
Due to the effect of Thermal Expansion, the Eiffel Tower is upto 15cm taller in summer.
If an atom were the size of a stadium, its electrons would be as small as bees. Comparable dimensions!!
If given the same mass, our body would actually be hotter than the Sun. The continuous conversion of chemical energy to thermal energy.
The only rock that floats in water is pumice. Its an igneous rock.
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In Young's Double Slit experiment following changes are observed if we change the parameters in following way:
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| DOUBLE SLIT ARRANGEMENT |
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| INTERFERENCE AND FRINGE FORMATION |
1. If wavelength of the incident light is increased the fringe spacing will be increased as it is directly proportional to the wavelength of the incident light but the contrast between the bright and dark fringes will not be affected.
2. If the double slit separation is increased the fringe spacing will be reduced as it is inversely proportional to the double slit separation but the contrast between the bright and dark fringes will not be affected.
3. If the distance from the double slits to the screen is increased the fringe spacing will be increased as it is directly proportional to distance between the double slit and screen but the contrast between the bright and dark fringes will be reduced as the intensity of the bright fringes will be reduced.
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No Physicist has ever seen ELECTRON.
Mass and Inertia resemble eachother.
Momentum is conserved in all types of collision.
The slope of velocity-time graph is acceleration.
ELECTRON VOLT is the unit of energy which is commonly used to estimate the smaller energy values.
An unbalanced object must produce acceleration.
Sound waves are longitudinal and mehanical wave.
Mass and Inertia resemble eachother.
Momentum is conserved in all types of collision.
The slope of velocity-time graph is acceleration.
ELECTRON VOLT is the unit of energy which is commonly used to estimate the smaller energy values.
An unbalanced object must produce acceleration.
Sound waves are longitudinal and mehanical wave.
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Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI), or magnetic resonance tomography (MRT) is a medical imaging technique used in radiology to visualize detailed internal structures. MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body.
An MRI machine uses a powerful magnetic field to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner—and this information is recorded to construct an image of the scanned area of the body. Magnetic field gradients cause nuclei at different locations to rotate at different speeds. By using gradients in different directions 2D images or 3D volumes can be obtained in any arbitrary orientation.
MRI provides good contrast between the different soft tissues of the body, which makes it especially useful in imaging the brain, muscles, the heart, and cancers compared with other medical imaging techniques such as computed tomography (CT) or X-rays. Unlike CT scans or traditional X-rays, MRI does not use ionizing radiation.
Click the link to download the file on MRI for A2 of Cambridge GCE A levels course. notes on MRI
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On a displacement-time graph …
-slope equals velocity.
-the "y" intercept equals the initial displacement.
-when two curves coincide, the two objects have the same displacement at that time.
-straight lines imply constant velocity.
-curved lines imply acceleration.
-an object undergoing constant acceleration traces a portion of a parabola.
-average velocity is the slope of the straight line connecting the endpoints of a curve.
-instantaneous velocity is the slope of the line tangent to a curve at any point.
-positive slope implies motion in the positive direction.
-negative slope implies motion in the negative direction.
-zero slope implies a state of rest.
-The area under the curve is meaningless
On a velocity-time graph …
-slope equals acceleration.
-the"y" intercept equals the initial velocity.
-when two curves coincide, the two objects have the same velocity at that time.
-straight lines imply uniform acceleration.
-curved lines imply non-uniform acceleration.
-an object undergoing constant acceleration traces a straight line.
-average acceleration is the slope of the straight line connecting the endpoints of a curve.
-instantaneous acceleration is the slope of the line tangent to a curve at any point.
-positive slope implies an increase in velocity in the positive direction.
-negative slope implies an increase in velocity in the negative direction.
-zero slope implies motion with constant velocity.
-the area under the curve equals the change in displacement.
On an acceleration-time graph …
-slope is meaningless.
-the"y" intercept equals the initial acceleration.
-when two curves coincide, the two objects have the same acceleration at that time.
-an object undergoing constant acceleration traces a horizontal line.
-zero slope implies motion with constant acceleration.
-the area under the curve equals the change in velocity.
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Nikola Tesla (10 July 1856 – 7 January 1943) was an inventor and engineer. He was an important contributor to the birth of commercial electricity, and is best known for his many revolutionary developments in the field of electromagnetism in the late 19th and early 20th centuries. Tesla's patents and theoretical work formed the basis of modern alternating current (AC) electric power systems, including the polyphase system of electrical distribution and the AC motor. This work helped usher in the Second Industrial Revolution.
Since the Nobel Prize in Physics was awarded to Marconi for radio in 1909, Thomas Edison and Tesla were mentioned in a press dispatch as potential laureates to share the Nobel Prize of 1915, leading to one of several Nobel Prize controversies. Some sources have claimed that because of their animosity toward each other neither was given the award, despite their scientific contributions; that each sought to minimize the other's achievements and right to win the award; that both refused to ever accept the award if the other received it first; and that both rejected any possibility of sharing it.
In the years after these rumors, neither Tesla nor Edison won the Prize (although Edison did receive one of 38 possible bids in 1915, and Tesla did receive one bid out of 38 in 1937).Earlier, Tesla alone was rumored to have been nominated for the Nobel Prize of 1912. The rumored nomination was primarily for his experiments with tuned circuits using high-voltage high-frequency resonant transformers.
In his honour the unit of magnetic flux density is TESLA (T).
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Question: What is the definition of electron? Even electron or proton has charge, what does it mean?
By Anjani Yadav
Answer:
The electron is a subatomic particle carrying a negative electric charge. It has no known components or substructure. Therefore, the electron is generally believed to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton.
In the Standard Model of particle physics, electrons belong to the group of subatomic particles called leptons, which are believed to be fundamental or elementary particles. Electrons have the lowest mass of any charged lepton (or electrically charged particle of any type) and belong to the first-generation of fundamental particles.
Electric charge is a physical property of matter which causes it to experience a force when kept near to other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two negatively charged objects. Positively charged objects and negatively charged objects experience an attractive force. As electron and proton both experience a force (either attractive or repulsive) they are called charged particles.
By Anjani Yadav
Answer:
The electron is a subatomic particle carrying a negative electric charge. It has no known components or substructure. Therefore, the electron is generally believed to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton.
In the Standard Model of particle physics, electrons belong to the group of subatomic particles called leptons, which are believed to be fundamental or elementary particles. Electrons have the lowest mass of any charged lepton (or electrically charged particle of any type) and belong to the first-generation of fundamental particles.
Electric charge is a physical property of matter which causes it to experience a force when kept near to other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two negatively charged objects. Positively charged objects and negatively charged objects experience an attractive force. As electron and proton both experience a force (either attractive or repulsive) they are called charged particles.
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Archimedes of Syracuse (Greek: Ἀρχιμήδης; c. 287 BC – c. 212 BC) was a Greek mathematician, physicist, engineer, inventor, and astronomer. Although few details of his life are known, he is regarded as one of the leading scientists in classical antiquity. Among his advances in physics are the foundations of hydrostatics, statics and an explanation of the principle of the lever. He is credited with designing innovative machines, including siege engines and the screw pump that bears his name. Modern experiments have tested claims that Archimedes designed machines capable of lifting attacking ships out of the water and setting ships on fire using an array of mirrors.
Archimedes is generally considered to be the greatest mathematician of antiquity and one of the greatest of all time. He used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, and gave a remarkably accurate approximation of pi. He also defined the spiral bearing his name, formulae for the volumes of surfaces of revolution and an ingenious system for expressing very large numbers.
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