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Little shop of physics
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About us
Units and measurement
1.1 Introduction
1.2 System of unit
1.2.1 Fundamental Quantities and Units
1.2.2 Derived Quantities and Units
1.2.3 Conventions for the use of SI Units
1.3 Measurement of length
1.3.1 Measurements of Large Distance
1.3.2 Measurement of Distance to Stars
1.3.3 Measurement of the Size of a Planet or a Star
1.3.4 Measurement of Very Small Distances
1.4 Measurement of mass
1.5 Measurement of time
1.6 Dimensions and dimensional analysis
1.7 Accuracy, precision & uncertainty in measurement
1.8 Errors in measurement
1.9 Significant error
Activity
Can you tell?
Quiz
Motion in a plane
2.1 Introduction
2.2 Rectilinear motion
2.3 Motion in two dimensions- motion in a plane
2.3.1 Average and Instantaneous Velocities:
2.3.2 Average and Instantaneous Acceleration
2.3.3 Motion for an Object travellinging a Plane with Uniform acc.
2.3.4 Relative Velocity
2.3.5 Projectile Motion
2.4 Uniform circular motion
Always Remember
Do you know
Quiz
Sound
3.1 Introduction
3.2 Common Properties of all Waves
3.3 Transverse Waves and Longitudinal Waves
3.4 The Speed of Travelling Waves
3.5 Principle of Superposition of Waves
3.6 Echo, reverberation and acoustics
3.7 Qualities of sound
3.8 Doppler Effect
Always remember
Do you know?
Activity
Quiz
Magnetism
4.1 Introduction
4.2 Magnetic Lines of Force and Magnetic Field
4.3 The Bar magnet
4.4 Gauss' Law of Magnetism
4.5 Earth’s Magnetism
Do you know ?
Try this
Quiz
EM waves & communication system
5.1 Introduction
5.2 EM wave
5.2.1 Sources of EM waves
5.2.2 Characteristics of EM waves
5.3 Electromagnetic Spectrum
5.3.1 Radio waves
5.3.2 Microwaves
5.3.3 Infrared waves
5.3.4 Visible light
5.3.5 Ultraviolet rays
5.3.6 X-rays
5.3.7 Gamma Rays
5.4 Propagation of EM Waves
5.4.1 Ground (surface) wave
5.4.2 Space wave
5.4.3 Sky wave propagation
5.5 Introduction to Communication System
5.5.1 Elements of a communication system
5.5.2 Commonly used terms in electronic communication system
5.6 Modulation
Do you know?
Quiz
References
Contact us
Little shop of physics
Home
About us
Units and measurement
1.1 Introduction
1.2 System of unit
1.2.1 Fundamental Quantities and Units
1.2.2 Derived Quantities and Units
1.2.3 Conventions for the use of SI Units
1.3 Measurement of length
1.3.1 Measurements of Large Distance
1.3.2 Measurement of Distance to Stars
1.3.3 Measurement of the Size of a Planet or a Star
1.3.4 Measurement of Very Small Distances
1.4 Measurement of mass
1.5 Measurement of time
1.6 Dimensions and dimensional analysis
1.7 Accuracy, precision & uncertainty in measurement
1.8 Errors in measurement
1.9 Significant error
Activity
Can you tell?
Quiz
Motion in a plane
2.1 Introduction
2.2 Rectilinear motion
2.3 Motion in two dimensions- motion in a plane
2.3.1 Average and Instantaneous Velocities:
2.3.2 Average and Instantaneous Acceleration
2.3.3 Motion for an Object travellinging a Plane with Uniform acc.
2.3.4 Relative Velocity
2.3.5 Projectile Motion
2.4 Uniform circular motion
Always Remember
Do you know
Quiz
Sound
3.1 Introduction
3.2 Common Properties of all Waves
3.3 Transverse Waves and Longitudinal Waves
3.4 The Speed of Travelling Waves
3.5 Principle of Superposition of Waves
3.6 Echo, reverberation and acoustics
3.7 Qualities of sound
3.8 Doppler Effect
Always remember
Do you know?
Activity
Quiz
Magnetism
4.1 Introduction
4.2 Magnetic Lines of Force and Magnetic Field
4.3 The Bar magnet
4.4 Gauss' Law of Magnetism
4.5 Earth’s Magnetism
Do you know ?
Try this
Quiz
EM waves & communication system
5.1 Introduction
5.2 EM wave
5.2.1 Sources of EM waves
5.2.2 Characteristics of EM waves
5.3 Electromagnetic Spectrum
5.3.1 Radio waves
5.3.2 Microwaves
5.3.3 Infrared waves
5.3.4 Visible light
5.3.5 Ultraviolet rays
5.3.6 X-rays
5.3.7 Gamma Rays
5.4 Propagation of EM Waves
5.4.1 Ground (surface) wave
5.4.2 Space wave
5.4.3 Sky wave propagation
5.5 Introduction to Communication System
5.5.1 Elements of a communication system
5.5.2 Commonly used terms in electronic communication system
5.6 Modulation
Do you know?
Quiz
References
Contact us
More
Home
About us
Units and measurement
1.1 Introduction
1.2 System of unit
1.2.1 Fundamental Quantities and Units
1.2.2 Derived Quantities and Units
1.2.3 Conventions for the use of SI Units
1.3 Measurement of length
1.3.1 Measurements of Large Distance
1.3.2 Measurement of Distance to Stars
1.3.3 Measurement of the Size of a Planet or a Star
1.3.4 Measurement of Very Small Distances
1.4 Measurement of mass
1.5 Measurement of time
1.6 Dimensions and dimensional analysis
1.7 Accuracy, precision & uncertainty in measurement
1.8 Errors in measurement
1.9 Significant error
Activity
Can you tell?
Quiz
Motion in a plane
2.1 Introduction
2.2 Rectilinear motion
2.3 Motion in two dimensions- motion in a plane
2.3.1 Average and Instantaneous Velocities:
2.3.2 Average and Instantaneous Acceleration
2.3.3 Motion for an Object travellinging a Plane with Uniform acc.
2.3.4 Relative Velocity
2.3.5 Projectile Motion
2.4 Uniform circular motion
Always Remember
Do you know
Quiz
Sound
3.1 Introduction
3.2 Common Properties of all Waves
3.3 Transverse Waves and Longitudinal Waves
3.4 The Speed of Travelling Waves
3.5 Principle of Superposition of Waves
3.6 Echo, reverberation and acoustics
3.7 Qualities of sound
3.8 Doppler Effect
Always remember
Do you know?
Activity
Quiz
Magnetism
4.1 Introduction
4.2 Magnetic Lines of Force and Magnetic Field
4.3 The Bar magnet
4.4 Gauss' Law of Magnetism
4.5 Earth’s Magnetism
Do you know ?
Try this
Quiz
EM waves & communication system
5.1 Introduction
5.2 EM wave
5.2.1 Sources of EM waves
5.2.2 Characteristics of EM waves
5.3 Electromagnetic Spectrum
5.3.1 Radio waves
5.3.2 Microwaves
5.3.3 Infrared waves
5.3.4 Visible light
5.3.5 Ultraviolet rays
5.3.6 X-rays
5.3.7 Gamma Rays
5.4 Propagation of EM Waves
5.4.1 Ground (surface) wave
5.4.2 Space wave
5.4.3 Sky wave propagation
5.5 Introduction to Communication System
5.5.1 Elements of a communication system
5.5.2 Commonly used terms in electronic communication system
5.6 Modulation
Do you know?
Quiz
References
Contact us
5.3.5 Ultraviolet rays
Ultraviolet rays were discovered by J. Ritter (1776-1810) in 1801.
They can be produced by the mercury vapour lamp, electric spark and carbon arc lamp.
They can also be obtained by striking electrical discharge in hydrogen and xenon gas tubes.
The Sun is the most important natural source of ultraviolet rays, most of which are absorbed by the ozone layer in the Earth’s atmosphere
Properties
1) They produce fluorescence in certain materials, such as 'phosphors'.
2) They cause photoelectric effect.
3) They cannot pass through glass but pass through quartz, fluorite, rock salt etc.
4) They possess the property of synthesizing vitamin D, when skin is exposed to them.
Uses
1) Ultraviolet rays destroy germs and bacteria and hence they are used for sterilizing surgical instruments and for purification of water.
2) Used in burglar alarms and security systems.
3) Used to distinguish real and fake gems.
4) Used in analysis of chemical compounds.
5) Used to detect forgery
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