Topic 2 - Electricity - Circuit Devices

Question 1

What is a cell and its use?

Answer 1

1. A cell is a single unit that converts chemical energy into electrical energy to produce a current (flow of electrons)
2. Cells are used to power small devices like flashlights, remote controls and clocks

Question 2

What is a battery and its use?

Answer 2

1. A battery is a collection of two or more cells connected in series or parallel to provide a higher voltage
2. Batteries power electronic devices like smartphones, laptops, and electric vehicles

Question 3

What is a fuse and its use?

Answer 3

1. A fuse is a safety device consisting of a thin wire that melts and breaks the circuit when excessive current flows through it
2. Fuses protect electrical appliances and circuits from damage due to overcurrent or short circuts

Question 4

What is a light emitting diode (LED) and its use?

Answer 4

1. An LED is a semiconductor device that emits light when an electric current flows through it in the forward direction
2. Used in displays, indicators, lighting etc

Question 5

What is a resistor and its use?

Answer 5

1. A resistor is a component that restricts the flow of electrical current, creating a voltage drop and dissipating energy as heat
2. Used to control current in circuits, set voltage levels and protect other components from voltage spikes

Question 6

What is a varible resistor and its use?

Answer 6

1. A variable resistor is a resistor whose resistance value can be adjusted
2. It is used for tuning and calibrating circuits, such as in volume controls or light dimmers

Question 7

What is an ammeter and its use?

Answer 7

1. An ammeter is an instrument used to measure electric current in a circuit
2. It is connected in series with a circuit to monitor the flow of current

Question 8

What is a voltmeter and its use?

Answer 8

1. A voltmeter is a device that measures the voltage (potential difference) across two points in a circuit
2. It is connected in parallel to a circuit to measure voltage without altering the circuits operation

Question 9

What is a diode and its use?

Answer 9

1. A diode is a semiconductor device that allows current to flow in one direction only, blocking it in the opposite direction
2. It is used for rectification in power supplies and protection against reverse polarity

Question 10

What is a light dependent resistor (LDR) and its use?

Answer 10

1. An LDR is a resistor whos resistance decreases with increasing light intensity
2. It is used in light-sensitive devices like automatic streetlights and alarm clocks

Question 11

What is a thermistor and its use?

Answer 11

1. A thermistor is a type of resistor whos resistance decreases with increasing temperatures
2. It is used for temperature sensing e.g. car engine temperature sensors and electronic thermostats