PHYSICS NOTES FOR FORM THREE We have:Notes 1 and Notes 2Notes 1To view the Notes, click the following links below: TOPIC 1 – APPLICATIONS OF VECTORS TOPIC 2 – FRICTION TOPIC 3 – LIGHT TOPIC 4 – OPTICAL INSTRUMENTS TOPIC 5 – THERMAL EXPANSION TOPIC 6 – TRANSFER OF THERMAL ENERGY TOPIC 7 – MEASUREMENT OF THERMAL ENERGY TOPIC 8 – VAPOUR AND HUMIDITY TOPIC 9 – THERMAL CURRENT ELECTRICITY Notes 2To view the Notes, click the following links below:1. APPLICATIONS OF VECTORS2. FRICTION3. LIGHT4. OPTICAL INSTRUMENTS5. THERMAL EXPANSION6. TRANSFER OF THERMAL ENERGY7. MEASUREMENT OF THERMAL ENERGY8. VAPOUR AND HUMIDITY9. CURRENT ELECTRICITYANSWERS TO NUMERICAL…
Author: Msomi Bora
TOPIC 9: THERMAL CURRENT ELECTRICITY Electromotive force (emf) and potential difference (pd) The Concept of Electromotive Force (emf) and Potential Difference (PD) Explain the concept of electromotive force (emf) and potential difference (pd) Potential difference (P.d) is the difference in potential between two charged points of conductor. It is measured in volts with the unit V. Electromotive force (e.m.f) is the voltage developed by any source of electrical energy such as a battery or dynamo. It is generally defined as the electrical potential for a source in a circui. It is measured in volt with the unit V. Internal Resistance (r)is…
TOPIC 8: VAPOUR AND HUMIDITY Vapour The Process of Evaporation of Liquid Explain the process of evaporation of liquid Vapours These are molecules which escape into the atmosphere after liquids are heated. When a liquid is heated strongly then molecules tends to escape ( those molecules are called vapour). Most liquids evaporates at any temperature however liquids may vary in the rate at which they evaporate at ordinary temperature. Alcohol and ether evaporate rapidly but lubricating oil and mercury hardly evaporate. Evaporation of a liquids result in the formation of vapour. Factors Affecting Evaporation of a Liquid Identify factors affecting…
TOPIC 7: MEASUREMENT OF THERMAL ENERGY Heat Capacity Heat capacity is the amount of heat required to raise the temperature of an object or substance by one degree. The temperature change is the difference between the final temperature ( Tf) and the initial temperature ( Ti). The Factors which Determine Heat Quality of a Substance Explain the factors which determine heat quality of a substance Heat is a form of energy transferred between bodies due to difference in temperature between them. The energy possessed by the body due to its temperature is called the internal thermal energy. The heat content is due to…
TOPIC 6: TRANSFER OF THERMAL ENERGY Conduction The Concept of Conduction of Heat Explain the concept of conduction of Heat Conduction is the transfer of heat energy through solids in the manner which particles do not move from one point to another, for example in metals. Generally, solid substances contain particles which are close together. Each particle vibrates at one position but cannot move to another position. The heated particles vibrate and collide with the other particles adjacent to them. In this way heat is transferred to the adjacent particles. The process goes on until the whole body get heated. Good…
TOPIC 5: THERMAL EXPANSION Thermal Energy The Concept of Heat Explain the concept of heat Heat energy (thermal energy) is the form of energy that causes the vibration of the particles of a substance. The more the vibrations the more the heat energy contained. Changes in the amount of heat energy contained in the substance cause changes in the temperature of the substance. Temperature – Is the degree of hotness or coldness of a body. SI Unit of Heat is Joule (J) The amount of heat content depends on the mass of the body, specific heat capacity and the change…
TOPIC 4: OPTICAL INSTRUMENTS Simple Microscope The Structure of the Simple Microscope Describe the structure of the simple microscope A magnifying glass, an ordinary double convex lens with a short focal length, is a simple microscope. For example, reading lens and hand lens. When an object is placed nearer such a lens than its principal focus, i.e., between the principal focus and the lens, an image is produced that is erect and larger than the original object. The image is also virtual; i.e., it cannot be projected on a screen as can a real image. The Mode of Action of…
TOPIC 3: LIGHT Light is a form of energy which controls the sense of vision. We are able to see things because of the light coming from them. Reflection of Light from Curved Mirrors Difference between Concave and Convex Mirrors Distinguish between concave and convex mirrors Concave mirror is a spherical mirror whose reflecting surface is curved inwards. A Good example is the driving mirror of a car. Convex mirror is a spherical mirror whose reflective surface is curved outwards. A good example of a convex mirror is a shaving mirror. General demonstrations of convex and concave mirrors (curved mirrors:…
TOPIC 2: FRICTION Concept of Friction The Concept of Friction Explain the concept for friction Friction is the force which opposes (resists) motion of the body. For example, a person will feel a certain resistance when pulling a block of wood resting on the table. The same kind of opposition can be felt when pushing a desk along a floor. That resistance (opposition) between two surfaces in contact is what we call friction. Friction force is always in opposite direction to the applied force. This means, for a body to move, the applied force must exceed the friction force. Friction…
TOPIC 1: APPLICATIONS OF VECTORS Scalar and Vector Quantities Difference between Scalar and Vector Quantities Distinguish between scalar and vector quantities Scalar Quantities These are physical quantities which have magnitude only. Examples of scalar quantities include mass, length, time, area, volume, density, distance, speed, electric current and specific heat capacity. Vector Quantities These are physical quantities which have both magnitude and direction. Examples of vector quantities include displacement, velocity, acceleration, force, pressure, retardation, and momentum. Addition of Vectors Using Graphical Method Add vectors using graphical method Scalar physical quantities have magnitude only. Thus, they can be added, multiplied, divided, or…
