Samll phyisics exam point

Look carefully
dispalacement travelled in t seconds is different from disaplacement travelled in t th second .

Heat

The relationship between linear expansivity and area expansivity:


The linear expansivity of a material is equal to half times the area expansivity of a material.
HENCE  area expansivity =2 x linear expansivity


The relationship between linear expansivity and volume expansivity:

The linear expansivity of a material equals to one third of the volume expansivity of the material.

HENCE volume expansivity = 3 x linear expansivity

These relationships should be remembered , because in the question only one form of linear expansivity will be given and you have to deduce the other forms.

Radioactivity

Todays chapter is all about 'Radioactivity' its very important in science exams

Radioactivity
Radioactivity is the change in the nucleus of the atom of an element
There are three different types of radioactivity
They are:

1. alpha [ ] radiation
2. Beta [ ] radiation
3. Gamma [ ] radiation
   When the nucleus emit these radiation the nucleus changes and a new atom of a different element is formed
   Alpha radiation
   1) It is giving out helium nucleus
   
   When this is given out the mass number of the nucleus decreases by 4 and the atomic number decreases by 2
   2) Its penetrating power is very low it can’t pass through even thin paper but a thin metal sheet can stop it.
   3) It is heavier than beta
   4) It is deflected by electric and magnetic field.

Beta radiation
1) One neutron in the nucleus changes to proton and electron and electron is given out as beta radiation
When this is given out the mass number of the nucleus does not change. The atomic number increases by 1
2) The penetrating power is higher than alpha particle. It can penetrate few centimeters of thin aluminum sheet but it can’t penetrate few centimeters of lead
3) It is light. It is deflected by electric and magnetic field

Three types of equilibrium

1.neutral equilibrium| eg a ball on a flat surface
2.stable equilibrium eg a ball in a downward curved surface
3.unstable equilibrium eg a ball on a moutain curved surface

Main types of thermometers and their specific uses

1.mercury glass thermometer- easy to use and take readings as the reding are already marked on the thermometer itself.

2.Gas thermometer - very sensitive and accurate as the expansion of gas is very high

3.Platinum wire resistence thermometer -measure temperatures that have a steady value
(mycar is used here because it is an good electric insulator but very fine conductor of heat)

4.Thermocouple - measure temperature at a point and also temperatures which are rapidly changing.

All the concepts of waves that are required for A Level Physics in animation form and very interactive

Welcome to the animated are of this blog where learning becomes fun.
All the knowledge and stuff that you will need to learn in your A Levels when studying waves and their property and oscillations are presented below in a animated way.Learn and enjoy.

Ppa6 Concep Tests Ch 11

What are our main purposes for the use of satellites ?

1.To transmit telecommunication messages to and fro .
2.To get weather news.
3.To get photos of the solar system or other planets.
4.