Chapter 5.3 _ Longman Physics 11-14 Questions
1) What is a diode? and draw its symbol.
2) Give one example of diode usage.
3) What is diffrence between LED and bulb?
4) What is the most common color of LED? How we can have a diffrent color?
5) An LED converts ____________ energey to ____________ energey.
6) How is an LDR structare?
7) Why semiconductors will allow some current to flow?
8) How a semiconeluetor could become a better conductor?
9) Give an example of LDR usage.
10) How a variable resistor control the size of o current?
11) Give an example of variable resistor?
12) How a dimmer switch can control the bightness of lights?
13) How a buzzer works? Give an example of buzzer usage.
14) How wires, plugs and sockets will be safe to touch?
15) Why we do not touch plugs and switches with wet hands?
16) If too high current flows through an electrical applince what might be happend and how we can protect that appliance about it?
17) What is fuse and how it can protect appliance about high current?
18) Why it is important that the correct fuse use in a plug?
19) We have a heater and we must use a proper fuse in it. Which one is better to chose?
A) 1A B) 3A C) 5A D) 13A
20) How we can prevent of wasting electical energy in the National Grid?
21) In the National Grid by which appliance we can change the voltage?
22) Name two types of transformer and what is their usage