CSEE (Form 4) Electric Circuits — practice questions

1. A voltmeter compares the potential at two points, so it needs to touch both ends of the component. 2. Voltmeters measure potential difference and must be connected in parallel. 3. An ammeter is the instrument that goes in series, because current has to flow through it. 4. Putting a voltmeter in series would break the path the current needs. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 17: Electric circuits_

1. Series means there is only one path, so the charge must pass through both resistors in turn. 2. The total resistance of resistors in series is the sum of the individual resistances. 3. Adding gives 4 ohm plus 6 ohm, which is 10 ohm. 4. The answer 2.4 ohm comes from using the parallel rule by mistake, which would lower the resistance instead of raising it. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 17: Electric circuits_

1. Adding resistors in parallel creates more paths along which current can flow. 2. More paths make it easier for charge to move, so the total resistance drops. 3. For two resistors in parallel the total is their product divided by their sum. 4. The product is 6 times 6, which is 36. 5. The sum is 6 plus 6, which is 12. 6. Dividing 36 by 12 gives 3 ohm. 7. The answer 12 ohm comes from adding them as if they were in series, which would raise the resistance instead. 8. Note that the total is always smaller than the smallest single resistor in a parallel set. _Source: Siyavula Physical Sciences Grade 10 (Everything Science, CC BY 4.0), Chapter 17: Electric circuits_