SI Units in Physics

What is the SI Unit?

SI (Système International) unit is an international system of measurements that are used universally in technical and scientific research to avoid the confusion with the units. Having a standard unit system is important because it helps the entire world to understand the measurements in one set of unit systems. Following is the table with base SI units:

Name of the Quantity	SI Unit	SI Unit Symbol
Length (l)	Meter	m
Mass (M)	Kilogram	kg
Time (T)	Second	s
Electric current (I)	Ampere	A
Thermodynamic temperature (Θ)	Kelvin	K
Amount of substance (N)	Mole	mol
Luminous intensity (J)	Candela	cd

Physics Definitions

This post contains all the important definitions of Physics that you need for your O-Level, A-Level, Matriculation, Intermediate level notes. All the definitions provide in very simple way which will help to understand and learn easily.

Measurement:

Scalar quantities are quantities in which the magnitude is stated, but the direction is either not applicable or not specified. Vector quantities are quantities in which both the magnitude and the direction must be stated. Random errors are errors of measurements in which the measured quantities differ from the mean value with different magnitudes and directions. Systematic errors are errors of measurements in which the measured quantities are displaced from the true value by fixed magnitude and in the same direction. Accuracy is a measure of how close the results of an experiment agree with the true value. Precision is a measure of how close the results of an experiment agree with each other.

Biology MCQs - Introduction to Biology

Biology [1^st Year | 11^th Class | Grade-11]
Multiple Choice Questions
Introduction to Biology

1.	Which one of the following is a correct sequence in biological methods?
	a. Observation – Hypothesis – Law – Theory	b. Observation – Hypothesis – deduction – testing of deduction ü	c. Hypothesis – observation – deduction – testing of deduction	d. Law – Theory – Deduction – Observation
2.	Which one of the following is not related to cloning?
	a. replacement of the nucleus of zygote, by another nucleus of the same organization ü	b. separation of cells of embryo to form more embryos	c. removal of piece of DNA or gene from the cell, and incorporation another gene or piece of DNA in its place	d. The individuals resulting have similar genetic makeup
3.	The study of distribution of animals in nature is called:
	a. zoogeography ü	b. biodiversity	c. geography	d. wild life
4.	Study of tissue is called:
	a. Microbiology	b. Morphology	c. Histology ü	d. Anatomy
5.	The branch of Biology which deals with the study of environment relations of organisms is called:
	a. Morphology	b. Ecology ü	c. Evolution	d. Zeeogeography

Ch-09: Transfer of Heat

Ch-09: Transfer of Heat

After studying this unit, the students will be able to:

• Recall that thermal energy is transferred from a region of higher temperature to a region of lower temperature.
• Describe in terms of molecules and electrons, how heat transfer occurs in solids.
• State the factors affecting the transfer of heat through solid conductors and hence, define the term Thermal Conductivity.
• Solve problems based on thermal conductivity of solid conductors.
• Write examples of good and bad conductors of heat and describe their uses.
• Explalin the convection currents in fluids due to difference in density.
• State some examples of heat transfer by convection in everyday life.

Ch-08: Thermal Properties of Matter

Ch-08: Thermal Properties of Matter 

After studying this unit, the students will be able to:

• Define temperature (as quantity which determines the direction of flow of thermal energy).
• Define heat (as the energy transferred resulting from the temperature difference between two objects).
• List basic thermometric properties for a material to construct a thermometer.
• Convert the temperature from one scale to another
• Describe rise in temperature of a body in terms of an increase in its internal energy.
• Define the terms heat capacity and specific heat capacity.
• Describe heat of fusion and heat of vaporization.
• Describe experiments to determine heat of fusion and heat of vaporization of ice and water respectively by sketching temperature-time graph on heating ice.

Ch-07: Properties of Matter

Ch-07: Properties of Matter 

After studying this unit, the students will be able to:

• State kinetic molecular model of matter (solid, liquid and gas forms).
• Describe briefly the fourth state of matter, i.e plasma.
• Define the term density.
• Compare the densities of a few solids, liquids and gases.
• Define the term pressure (as a force acting normally on unit area).
• Explain how pressure varies with force and area in the context of everyday examples.
• Explain that the atmosphere exerts a pressure.
• Describe how the height of a liquid column may be used to measure the atmospheric pressure.
• Describe that atmospheric pressure decreases with the increase in height above the Earth's surface.
• Explain that changes in atmospheric pressure in a region may indicate a change in the weather.
• State Pascal's law.
• Apply and demonstrate the use with examples of Pascal\'s law.

Ch-06: Work & Energy

Ch-06: Work & Energy 

After studying this unit, the students will be able to:

• Define work and its SI unit.
• Calculate word done using equation: Work = force x distance moved in the direction of force
• Define energy, kinetic energy and potential energy. State unit of energy.
• List the different forms of energy with examples.
• Describe the processes by which energy is converted from one form to another.
• State mass energy equation E-mc2 and solve problems using it.
• Describe the process of electricity generation by drawing a block diagram of the process from fossil fuel input to electricity output.
• List the environmental issues associated with power generation.

Ch-05: Gravitation

Ch-05: Gravitation

After studying this unit, the students will be able to:

• State Newton's law of gravitation.
• Explain that the gravitational forces are consistent with Newton's third law.
• Explain gravitational field as an example of field of force.
• Define weight (as the force on an object due to gravitational field).
• Calculate the mass of Earth by using law of gravitation.
• Solve problems using Newton's of gravitation.

Ch-04: Turning Effects of Force

Ch-04: Turning Effects of Force 

After studying this unit, the students will be able to:

• Define like and unlike parallel forces.
• State head to tail rule of vector addition of forces / vectors.
• Describe how a force is resoved into its perpendicular components.
• Determine the magintude and direction of a force from its perpendicular components.
• Define moment of force or torque as moment = force x perpendicular distance from pivot to the line of action of force.
• Explain the turning effect of force by relating it to everyday life. - State the principle of moments.
• Define the centre of mass and centre of gravity of a body.
• Define couple as a pair of forces tending to produce rotation.
• Prove that the couple has the same moments about all points.

Ch-03: Dynamics

Ch-03: Dynamics

After studying this unit, the students will be able to:

• Define momentum, force, inertia, friction and centripetal force.
• Solve problems using the equation Force = change in momentum / change in time.
• Explain the concept of force by practical examples of daily life.
• State Newton's laws of motion.
• Distinguish between mass and weight and solve problems using F=ma, and w=mg.
• Calculate tension and acceleration in a string during motion of bodies connected by the string and passing over frictionless pulley using second law of motion.
• State the law of conversation of momentum.
• Use the principle of conservation of momentum in the collision of two objects.

Ch-02: Kinematics

Ch-02: Kinematics

After studying this unit, the students will be able to:

• Describe using examples how objects can be at rest and in motion simultaneously.
• Identify different types of motion i.e translatory (linear random and circular); rotatory and vibratory motions and distinguish among them.
• Differentiate with examples between distance and displacement, speed and velocity.
• Differentiate with examples between scalar and vector quantities.
• Represent vector quantities by drawing.
• Define the terms speed, velocity and acceleration.
• Plot and interpret distance-time graph and speed-time graph.
• Determine and interpret the slope of distance-time and speed-time graph.

Ch-01: Physical Quantities and Measurements

Ch-01: Physical Quantities and Measurements

After studying this unit, the students will be able to:

• Describe the crucial role of Physics in Science, Technology and society.
• Explain with examples the Science is based on physical quantities which consist of numerical magnitude and a unit.
• Differentiate between base and derived physical quantities.
• List the seven units of System International (SI) alongwith their symbols and physical quantities (standard definitions of SI units are not required).
• Interconvert the prefixes and their symbols to indicate multiple and sub-multiples for both base and derived units.

Physics Symbols

What is the Importance of Physics Symbols?

In Physics, different symbols or documentations are utilized to mean various amounts. The indications make the portrayal of the amounts simpler. In this page, probably the most well known physics symbols are referenced. Let us assume that a lady drives her car at a speed of 30 kmph and reaches her hometown in 2 hrs and if she drives at 50 kmph, she reaches in 1.5 hr. So, if we have to represent these units as symbols, how can we do that?

Symbols used for physical quantities are vastly different. Sometimes, the symbol may be the first letter of the physical quantities they represent, like ‘d’, which stands for distance. Other times, they may be completely unrelated to the name of the physical quantities, such as c symbolises the speed of light.

Ch-12: Geometrical Optics

Chapter-12: Geometrical Optics 

Here this post contains Short Question and Answers of Chapter 12: "Geometrical Optics". Learn these question answers and other related stuff for exam preparation. 

Geometrical optics is a branch of optics where light is described by rays. Light rays are conceived as geometrical lines originating from sources, extending through media, and being revealed by detectors; their directions account for paths along which light flows.

Ch-11: Sound

Ch-11: Sound 

Here this post contains Short Question and Answers of Chapter 11: "Sound". Learn these question answers and other related stuff for exam preparation. 

A sound is a type of energy, very much like power, intensity or light. Sound is one of the significant feelings of the human body. A few sounds are wonderful, and some are irritating. We are exposed to different kinds of sound all time. Sound is a vibration that spreads as an acoustic wave, through a transmission medium