level: Electrical Power
Questions and Answers List
level questions: Electrical Power
| Question | Answer |
|---|---|
| what is considered a powerful object in physics | an object that gets work done quickly |
| what is power? | the rate at which energy is transferred in Watts energy transferred per unit time |
| What is one Watt equivalent to? | 1 Joule of energy transferred in 1 second |
| what is the formula for power when given an energy and a time | P=E/t |
| do high power appliances ( those that transsform electrical energy to produce heat and consume power) draw a large or little current? | large current |
| what are the four relationships for calculating power? | P=E/t P=IV P=I^2R P= V^2/R |
| What is a fuse? | A safety device used to protect the flex of an appliance or the wiring of a circuit |
| what will happen if too much current flows through a fuse? | insulated surrounding copper wire may melt, which leads to exposed wires |
| what are fuses typically made from? | short lengths of wire which melt if current exceeds a certain value. This value is determined by the wire type or thickness |
| what two current ratings to UK fuses usually come with? | 3A or 13A |
| how do you ensure you select the right fuse | you must know an appliances power, with this you need to calculate the appliances current (assuming it is plugged into 230V mains) with P=IV. The fuse must be large enouigh to allow the appliance to work normally. |