UNDERSTANDING SPECIFIC LATENT HEAT

*  CHANGES IN THE STATE OF MATTER CAN BE EXPLAINED BY USING HEATING CURVE AND COOLING CURVE

* HEATING CURVE :
SOLID TO LIQUID TO GAS

* COOLING CURVE :
GAS TO LIQUID TO SOLID

*  SPECIFIC LATENT HEAT :

- AMOUNT OF HEAT ENERGY REQUIRED TO CHANGE THE STATE OF 1 KG OF SUBSTANCE AT CONSTANT TEMPERATURE

- FORMULA :

HEAT ENERGY INVOLVED / MASS OF SUBSTANCE

- UNIT :

* SPECIFIC LATENT HEAT OF FUSION :

- AMOUNT OF HEAT ENERGY REQUIRED BY COMPLETELY CHANGE 1 KG OF A LIQUID TO THE GASEOUS STATE WITHOUT CHANGES IN TEMPERATURE

- SOLID TO LIQUID | LIQUID TO SOLID

* SPECIFIC LATENT HEAT OF VAPORISATION :

- AMOUNT OF HEAT ENERGY REQUIRED TO COMPLETELY CHANGE 1 KG OF A LIQUID TO THE GASEOUS STATE WITHOUT CHANGE IN TEMPERATURE

- LIQUID TO GAS | GAS TO LIQUID

* APPLICATIONS :

- STEAMING FOOD ( THE CONDENSED WATER VAPOUR RELEASES A LARGE AMOUNT OF LATENT HEAT WHEN THE FOOD IS STEAMED )

- PRESERVATION OF FOOD ( PRESERVED BY ICE TO MAINTAIN FRESH FOR A LONGER PERIOD )

- KILLING OF BACTERIA AND GERMS

UNDERSTANDING WAVES

* WAVE :
SPREADING OF DISTURBANCE FROM A VIBRATING OR OSCILATING MOTION PHENOMENON THAT ENERGY IS TRANSFERRED THROUGH VIBRATION

* EXAMPLE :
LIGHT , WATER , SOUND AND ELECTROMAGNETIC WAVES

* TYPES :

- TRANSVERSE WAVE - THE OSCILLATIONS ARE AT RIGHT ANGLES TO THE DIRECTION OF TRAVEL ( LIGHT WAVES AND WATER - WAVES )

- LONGITUDINAL WAVE - THE OSCILLATIONS ARE PARALLEL TO THE DIRECTION OF TRAVEL ( SOUND WAVES )

* SIMILARITIES BETWEEN TRANSVERSE WAVE AND LONGITUDINAL WAVES :
- PRODUCED BY VIBRATION OR OSCILLATION
- PROPAGATED BY VIBRATION OR OSCILLATION OF MEDIUM PARTICLES
- CARRY ENERGY OR MOMENTUM WITHOUT TRANSFERRING MATTER

* DIFFERENCES BETWEEN TRANSVERSE WAVES AND LONGITUDINAL WAVES :
 TRANSVERSE WAVES :
- PERPENDICULAR DIRECTION OF PROPAGATION
- PERPENDICULAR POSITION OF MINIMUM AND MAXIMUM DISPLACEMENT
 LONGITUDINAL WAVES :
- PARALLEL DIRECTION OF PROPAGATION
- PARALLEL POSITION OF MINIMUM AND MAXIMUM DISPLACEMENT

* WAVEFRONT :

- IMAGINARY LINE ON A WAVE OVER WHICH PARTICLES ARE VIBRATING IN THE SAME PHASE

- DIVIDED INTO TWO :

CIRCULAR WAVEFRONT

PLANE WAVEFRONT

* CREST :

HIGH POINT

* TROUGH :

LOW POINT

* AMPLITUDE :
MAXIMUM DISPLACEMENT FROM THE RESTING POSITION

* PERIOD :
TIME TAKEN TO GENERATE ONE COMPLETE OSCILLATION

* FREQUENCY :
NUMBER OF COMPLETE OSCILLATIONS OCCUR IN ONE SECOND | 1 / PERIOD

* WAVELENGTH :
DISTANCE BETWEEN TWO SUCCESSIVE CRESTS OR TROUGHS

* WAVESPEED :
DISTANCE MOVED BY A WAVE IN ONE SECOND

* RELATIONSHIP BETWEEN FREQUENCY , WAVELENGTH , AND WAVESPEED :

* DAMPING :

- A PROCESS WHERE OSCILLATIONS DIE DOWN TO LOSS OF ENERGY
- WHEN AN OSCILLATING SYSTEM IS LOSING ENERGY TO ITS SURROUNDINGS , THE SYSTEM IS SAID TO BE DAMPED

- INTERNAL : CAUSED BY COMPRESSION AND RAREFRACTIONS OF MOLECULES

- EXTERNAL : CAUSED BY FRICTION BETWEEN THE OSCILLATION SYSTEM AND AIR

- EFFECTS : AMPLITUDE DECREASES , ENERGY DECREASES , FREQUENCY DOES NOT CHANGE AS THE PERIOD REMAIN CONSTANT

* RESONANCE :

- EXTERNAL FORCE MUST BE APPLIED TO KEEP AN OSCILLATING SYSTEM TO GO ON CONTINUOUSLY
- RESONANCE OCCURS WHEN AN OSCILLATOR IS ACTED BY A SOURCE OF ENERGY WHOSE FREQUENCY EXACTLY MATCHES THE NATURAL FREQUENCY OF THE OSCILLATOR

- EFFECTS : PRODUCTION OF LOUD SOUND FROM MUSICAL INSTRUMENTS ,  OVER-MUCH NOISE FROM A MOVING BUS , THE RADIO AND TV TUNE CAN BE USED TO SELECT A CERTAIN PROGRAMME , A SUSPENDED BRIDGE CAN COLAPSE IF BLOWN BY STRONG WINDS