Resisting Flashcards
The higher the resistance.
The lower the current.
The higher the current.
The brighter the bulb in a circuit. The faster the motor turns.
Resistance Eq.
resistance = voltage/current
Current Eq.
current = voltage/resistance
Voltage Eq.
voltage = current x resistance
What does the resistance of a wire depend on?
The resistance depends on the length of the wire.
How does a resistor work?
A variable resistor works by changing the length of the wire in the circuit; the longer the wire, the greater the resistance.
What is the shape of a voltage-current graph of a resistor?
The voltage-current graph for a resistor is a straight line passing through the origin. This shows that voltage is proportional to current. A resistor obeys Ohm’s law.
Gradient of the voltage-current graph for a fixed resistor.
The steeper the gradient of the voltage-current graph the greater the resistance. For a fixed resistor, the gradient is equal to the to the resistance.
What is the shape of a voltage-current graph of a bulb?
The voltage-current graph for a bulb is not a straight line passing through origin. The gradient of the line increases as the current increases. A bulb does not obey Ohm’s law.
What happens to the resistance of a filament bulb as current increases?
The resistance of a filament bulb increases as the current increases.
What happens to the electrons in a filament bulb?
- When electrons collide with the atoms in the filament, it makes the atoms vibrate more. This increased vibration leads to:
- An increased number of collisions so the resistance increases.
- An increase in the temperature of the filament.
