13 Circuits - 4th Form Flashcards
Why are the bulbs dimmer in the second circuit?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/713/q_image_thumb.jpg?1528218808)
Voltage is shared between bulbs in series
Less voltage across each bulb therefore bulb is dimmer.
Define voltage
Energy per unit charge either supplied by a cell, or transferred to a component.
What component symbol is shown below?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/717/q_image_thumb.jpg?1527840224)
Light dependent resistor
What is voltage measured in?
Volts or V
What is the voltage across a cell or power supply a measure of?
The energy transferred from chemical store electrically to the wires per coulomb
What component symbol is shown below?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/721/q_image_thumb.jpg?1527840355)
bulb
What component symbol is shown below?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/722/q_image_thumb.jpg?1527840470)
ammeter
Define current
- The rate of flow of charge
OR
- the number of coulombs passing a point in a circuit per unit time
(It is not the speed of the electrons!)
What happens to the total resistance and current in a circuit as more bulbs are added in parallel
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/725/q_image_thumb.jpg?1528219415)
Adding bulbs in parallel decreases the total resistance
V=IR
I = V / R
as resistance decreases, current increases for the same voltage
How will the current change if the resistance of a circuit is decreased for the same voltage?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/727/q_image_thumb.jpg?1604842592)
current will increase
To investigate how the currect varies with voltage in a filament bulb, fixed resistor and diode you should use the cirucit below.
Why does the circuit need a variable resistor?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/730/q_image_thumb.png?1604830911)
To vary the voltage across the component
Independent variable is voltage
Dependent variable is current
What is resistance?
- The tendency of a material to resist the flow of an electrical current.
- A measure of how much voltage is needed per amp of current.
How does the resistance vary with light intensity on a LDR?
As light intensity increases, resistance decreases
![](https://s3.amazonaws.com/brainscape-prod/system/cm/420/969/732/a_image_thumb.png?1604843186)
What is a volt?
1 V = 1 J/C
1 volt = 1 joule per coulomb
How does voltage related to current and resistance?
V=IR