Physics Form 4 Keywords

PHYSICS FORM 4 KEYWORDS

CHAPTER 1: INTRODUCTION TO PHYSICS

1. Base quantities is a physical quantities that cannot be defined in terms of other physical quantities.
2. Derived quantities is a physical quantities that derived from combination of base quantities through multiplication, division or both.
3. Scalar quantities is a physical quantities which have magnitude only.
4. Vector quantities is a physical quantities which have magnitude and direction.
5. Systemic errors are errors caused by the condition of the measuring instrument or environment when measurement are taken.
6. Random errors are errors due to mistakes made when measurements are taken either through incorrect positioning of the eye or sudden change of environment factors.
7. Zero error is a measuring instrument that does not exactly start from zero.
8. Parallax error is an error due to the incorrect positioning of the eye when taking a reading.
9. Consistency is the ability of a measuring instrument to give readings with a very small deviation or no deviation from the mean value.
10. Accuracy is the ability of a measuring instrument to give readings nearest or almost equal to the actual value.
11. Sensitivity is the ability of a measuring instrument to detect a very small changes in the quantity being measured.

CHAPTER 2: FORCES AND MOTION

1. Linear motion is the total length of the path travelled of the path travelled by an object from one point to the other.
2. Acceleration is the change of velocity against time.
3. Inertia is the tendency of an object to maintain its state of rest or uniform motion in a straight line unless it is acted upon by an external force.
4. Newton's First Law- An object which is at rest will remain stationary or a moving object will move with constant velocity if there is no external forces acting on it.
5. Momentum is the product of mass of an object and its velocity.
6. Newton's Second Law of Motion- When a net force acts on the object, the acceleration of the object is directly proportional to the net force and has a magnitude that is inversely proportional to its mass.
7. Impulse is the product of impulsive force, F acting on an object for a time of impact, t.
8. Impulsive force ia a large force that acts over a short period of time during collision or explosion.
9. Gravitational field strength, g is the gravitational force acting on a unit mass in the field.
10. Gravitational acceleration is the acceleration of an object due to the pull of the gravitational force.
11. Weight, W is the measurement of the gravitational force on the body.
12. Mass, m is the measurement of the quantity of matter in the body.
13. Forces in equilibrium is where an object is said to be in equilibrium when all the forces that act on the object are balanced in all directions.
14. Newton's Third Law of Motion- For every action, there is an equal and opposite reaction.
15. Resultant force is the forces acting on a body can be combined into a single force.
16. Work is done when a force alter the direction of the object to move towards the direction of the force applied.
17. Energy is the potential or the ability to do work.
18. Potential energy is energy possessed by an object due to its hsape or position.
19. Gravitational potential energy is energy carried by an object due to its different height above the Earth surface.
20. Power, P is the rate of which work is done or rate of energy transformed.
21. Efficiency is the percentage of the input energy that is transformed to a useful form of output energy.
22. Elasticity is the ability of an object to return to its original shape and dimensions when the applied external force is removed.
23. Hooke's Law is the extension or compression of a spring is directly proportional to the force acting on it provided the elastic limit of the spring is not exceeded.
24. Spring constant, k indicates the stiffness or hardness of the spring.

CHAPTER 3: FORCES AND PRESSURE

1. Pressure is the perpendicular force acting on a unit area.
2. Manometer is used to measure the differences in gas or liquid pressure.
3. Bourdon Pressure Gauge is used to measure a very high pressure.
4. Archimedes' Principle: When an object is totally or partially immersed in a fluid, the upthrust or buoyant force on its equal to the weight of fluid displaced.
5. Principle of floatation is the weight of an object floatingon the surface of a liquid is equal to the weight of the liquid displaced by the object.\
6. Bernoulli's Principle- In a steady flow of fluid (liquids and gases), the pressure in the fluid is low when the velocity of the fluid is high and vice versa.
   
   
   CHAPTER 4: HEAT

1. Temperature is the degree of hotness.
2. Heat is a form of energy.
3. Thermal equilibrium is a condition where two objects in thermal contact reach the same temperature and no net heat transfers between them.
4. Specific heat capacity is the amount of heat energy required to increase the temperature of 1kg of the substance by 1 degree Celcius or 1 Kelvin (K).
5. Sea breeze is the movement of cool air from the sea towards the land.
6. Land breeze is the movement of cool air from the land towards the sea.

CHAPTER 5: LIGHT

1. Light is a form of energy.
2. Light rays are the path and direction which light energy flows.
3. Regular reflection is when the light is reflected from a smooth surface in one direction only.
4. Diffuse reflection is when the light is reflected from an uneven surface and is scattered in all directions.
5. Laws of Reflection- The angle of incident, I is equal to the angle of reflection, r.
6. Refraction of Light- The bending of light rays when it passes from one medium to another due to different optical densities and change in the velocity of light.
7. Law of Refraction- The incident ray, refracted ray and the normal at the point of incidence, all lie on the same plane.
8. Real depth, D is the distance of the real object, O from the surface of the water.
9. Apparent depth, d is the distance of the image, I from the surface of the water.
10. Power of lenses is a measure of the ability of the lens to converge or diverge an incident beam of light.