What is the relationship between resistance and current in an electrical circuit?

Higher resistance reduces current, making it more difficult for charges to flow, while lower resistance increases current, allowing for easier flow.

Fill in the blank: In a circuit with one cell and a bulb, adding more bulbs in ___ increases resistance, causing the indicator bulb to dim.

Series

True or False: Increasing resistance in a circuit will always increase the amount of current flowing through it.

False. Increasing resistance actually decreases the current flowing through the circuit.

Riddle: I oppose the flow of electric charges and can cause energy to turn into heat. What am I?

A resistor

How does the collision of electric charges with metal atoms in a resistor affect the flow of current?

The collisions transfer energy to the metal atoms, which heats the resistor and slows down the charges, opposing their flow.

Fill in the blank: Resistance is measured in ___, which quantifies how much a material opposes the flow of current.

Ohms

What happens to the current when resistivity of a material is high?

When the resistivity of a material is high, the current decreases because it is harder for charges to flow through the material.

Multiple Choice: What effect does adding resistors in series have on total resistance? A) Increases B) Decreases C) No effect D) Fluctuates

A) Increases

What is the primary use of good conductors like copper and aluminum in electrical circuits?

Good conductors like copper and aluminum are used in electrical circuits primarily for wiring due to their minimal energy loss during current flow.

Fill in the blank: Insulators, such as plastic and glass, have ___ resistance, preventing current flow.

Extremely high

True or False: Insulators can never conduct electricity, regardless of the voltage applied.

False. Insulators can conduct electricity at very high voltages, such as air conducting lightning at millions of volts.

Which materials are considered semi-conductors, and how do they behave with changes in voltage or temperature?

Silicon and germanium are semi-conductors.

• Common semi-conductors used.

• Resistance changes with conditions.

• Key for electronic devices.

Riddle: I am known for keeping wires safe and have the ability to resist the flow of electricity. What am I?

An insulator

What factors determine the resistance of an object, and how does this differ from resistivity?

Resistance depends on length and shape.

• Length increases resistance.

• Thickness reduces resistance.

• Resistivity is material-specific.

Fill in the blank: Medium-bad conductors, such as tungsten and graphite, are used in components like ___ or ___ where resistance produces heat or light.

Bulbs; heaters

Short Answer: Explain why good conductors allow easy current flow.

Good conductors allow easy current flow because they have many free electrons that can move between atoms, facilitating the flow of electricity.

Electrons are pulled by electric force and collide with ___ in metal atoms, which causes vibrations that heat the material.

Positive nuclei

What is the resistivity of copper compared to silver and gold?

Copper has moderate resistivity, while silver and gold have very low resistivity.

Fill in the blank: A multimeter set to the resistance range measures resistance in ___.

Ohms

True or False: The resistance of a carbon resistor changes significantly with temperature.

False; carbon resistors maintain constant resistance, ensuring consistent performance.

If a nichrome wire has a voltage of 6 V and a current of 2 A, what is its resistance?

3 Ω

Riddle: I am a material that can be cut to adjust my resistance, and I often have colored bands to indicate my value. What am I?

A carbon resistor

What formula is used to find voltage when current and resistance are known?

V = I × R

At 1 ampere, how many electrons pass a point per second?

6.25 × 10^18 electrons

Fill in the blank: Very low resistivity materials include silver, copper, gold, and ___.

Aluminium