This document provides an overview of the AS Level Physics course and discusses key concepts related to physical quantities, including: 1. Physical quantities can be quantified by measurement and have units associated with them. There are two types: base quantities and derived quantities. 2. Base quantities are the seven SI base units: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. Derived quantities are formed by mathematical relationships between base quantities. 3. When writing the units of a derived quantity, the formula is used to express the units in terms of the base units. Examples of deriving units for acceleration, force, and pressure are provided.

1. CI Advanced Subsidiary Level PhysicsCourse Code: 9702

2. Physics 9702AS & A2

3. The A Levels Physics course: Resource Materials: cie.org.uk http://www.xtremepapers.net/ http://asphysics.edublogs.org/

7. A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement. E.g.: If the temperature T of a body is quantified (measured) as 300 kelvin this is written T = 300 x K = 300 K where T is the symbol for the physical quantity, and K is the symbol for the unit. What is a Physical Quantity

8. Physical Quantities are of two types: Base quantities Derived quantities

9. Base Quantities

10. Derived quantities:

11. For Derived Quantities When you are asked to write the units of a derived quantity in terms of its “base units”, then you recall its respective formula: Example: Volume=l*b*h hence base units=m Area=l*l hence base units= m Speed=distance/time hence base units=m/s Therefore; as a golden rule, you are just supposed to recall the base units of the 7 base quantities we talked about and the rest would all be provided in the Question. Till now, we talked about general units of derived quantities, that’s why we didn’t say that derived quantities have SI units (remember how I said that Volume can have the units of liters, m ,cm ,dm ). Now we will look at the concept of SI “base units” and their nexus with derived quantities. 3 3 3 3 2 The Base Units Concept

12. Recall how I said that the units on the LHS and the RHS of the equal sign should be the same: i.e. Suppose A=MD/C The base units of A are Kgmsec /m M=kg D=m Then find the base units of the quantity C. Make C the subject: C=MD/A, C=kg*m/kgmsec /m C=m/sec Q1. Units of acceleration. Q2. Find the units of Force using the formula: F=ma Q3. Units of Pressure? P=pgh 2 2 2

13. Labeling Graphs: X axis independent quantity Y axis dependent quantity (Recall speed-time) Table Columns: Time

15. Class Test Convert the following quantities into different SI prefixes. Show your entire working. An answer without working would earn a straight ‘zero’ Use the symbols for the units in your answer. Use of the standard form where appropriate will earn you extra credit All questions carry 2 marks 1. 145.56s to milliseconds (ms) 2. 127845.64ms to seconds (s) 3. 123923593426.2 microseconds (μs) to seconds (s) 4. 67000.75 km to m 5. 65.7mm to km 6. 85.9km to mm 7. 6.7m to μm (micrometer) 8. 7800540032.54μm to km 9. 7807.089J (joules) to MJ (mega joules) 10. 6574.56 MJ to J

16. After you will be done with the A 'level syllabus, you will be in a position to give a rough estimate of quantities you have studied in your course. ‘ Till now, you can give a rough estimate of quantities like: height of the door? diameter of pencil / pencil lead volume of brick / liquid in drinking cup mass of brick / person / nail time between your hiccups? Just to give you a feel of what kind of estimate questions you can see in your past papers:

17. May/June 2008, Paper 2, question 1

19. Thank you Be the Change that you want to witness in the World.