Circuits

Question 1

Describe the function of a thermistor

Answer 1

the resistance of the circuit depends on the temperature , if temperature increases resistance decreases

Question 2

What is the function of LDR

Answer 2

the resistance depends on the light intensity , so if light intensity increases then resistance decreases

Question 3

Describe the function of diode

Answer 3

allow current to flow in one direction only , can be used to covert AC to DC

Question 4

Describe role of LED

Answer 4

emits light when a current passes through it

Question 5

what are the three key rules for a circuit

Answer 5

• ammeter is always in series with components
• voltmeter is anyways parallel to components
• the direction of current is always from positive to negative

Question 5

what are the three key rules for a circuit

Answer 5

• ammeter is always in series with components
• voltmeter is anyways parallel to components
• the direction of current is always from positive to negative

Question 6

define potential difference

Answer 6

amount of energy transferred per unit of charge passing through terminals

Question 7

what does the definition of potential difference mean

Answer 7

that one volt = one joule per coulomb

Question 8

compare distribution of current in series circuit and parallel circuit

Answer 8

current is same everywhere in series whereas in parallel it spilts up at junctions

Question 9

compare potential difference in series and parallel circuits

Answer 9

in series circuit potential difference is shared amongst components whereas in parallel circuits voltage is same across all components

Question 10

compare resistors in series and parallel circuits

Answer 10

in series circuits total resistance is sum of resistance of all components whereas in a parallel circuit the resistance decreases if u add another resistor as current can take more than one pathway

Question 11

what is the benefit of more resistors in series circuit

Answer 11

more resistance to travel through as two resisters are better than one so higher number of collisions

Question 12

Core Practical : Explain the components when investigating a fixed resistor or filament lamp

Answer 12

voltmeter , fixed resistor and/not variable resistor, ammeter , cell

Question 13

Core Practical: Explain what you do after setting up circuit

Answer 13

change the voltage by reducing resistance on variable resistor or increasing output potential difference altering the current

Question 14

Core Practical : Identify what you do after altering potential difference

Answer 14

take reading of the current using ammeter to observe how current changes due to varying potential difference - do this with a filament lamp aswell

Question 15

Core Practical: Why should you plot an I-V graph after collecting readings

Answer 15

work out the resistance using P = IR

Question 16

Core Practical: what is the result of this practical

Answer 16

potential difference is directly proportional to current if resistant is constant this is correct for fixed resistor

Question 17

Core Practical: identify the shape of line for filament graph and explain why

Answer 17

current is not directly proportional to voltage because as current increases the temperature will increase causing resistance to increase