resistance Flashcards
What is resistance in an electrical circuit?
Resistance is a measure of the opposition to the flow of electric current.
What is the unit of resistance?
The unit of resistance is the ohm, symbolized by the Greek letter omega (Ω).
True or False: Higher resistance means more current flows through a circuit.
False.
What is Ohm’s Law?
Ohm’s Law states that voltage (V) equals current (I) times resistance (R), or V = I × R.
Fill in the blank: The formula for calculating resistance is R = V / ___.
I
What factors affect the resistance of a conductor?
The factors include the material, length, cross-sectional area, and temperature of the conductor.
Which material typically has the lowest resistance?
Copper.
True or False: Increasing the length of a conductor increases its resistance.
True.
What is the relationship between temperature and resistance in most conductors?
In most conductors, resistance increases with an increase in temperature.
What is a resistor?
A resistor is a component used in electrical circuits to provide a specific amount of resistance.
What is the purpose of a variable resistor?
A variable resistor allows the resistance to be adjusted within a circuit.
Fill in the blank: Resistance is measured using a device called a ___.
multimeter
What happens to the total resistance in a series circuit?
The total resistance is the sum of all individual resistances.
What happens to the total resistance in a parallel circuit?
The total resistance is less than the smallest individual resistance.
True or False: In a parallel circuit, the voltage across all components is the same.
True.
What is the term for materials that have very high resistance?
Insulators.
What is the effect of adding more resistors in series?
It increases the total resistance.
What is the effect of adding more resistors in parallel?
It decreases the total resistance.
Fill in the blank: Ohm’s law can be rearranged to find current as I = V / ___.
R
What is a superconductor?
A superconductor is a material that can conduct electricity without resistance when cooled below a certain temperature.
True or False: All conductors have some resistance.
True.
What is the term for the resistance due to temperature changes?
Temperature coefficient of resistance.
What is the typical resistance value of a standard carbon resistor?
Typically, values range from a few ohms to several megaohms.
What is the role of a fuse in a circuit?
A fuse protects the circuit by breaking the connection if the current exceeds a safe level.
What is the significance of resistor color codes?
Resistor color codes indicate the resistance value and tolerance of a resistor.
Fill in the blank: A resistor with a low resistance value will allow a ___ current to flow.
high
