Presentation on theme: "April 26/28 Physics. Table of Contents #. Date Title-Page – Page Number 29.April 14/15 Electrostatics 30.April 18/19 Electric Field 31.April 20/21 Electrostatics."— Presentation transcript:
April 26/28 Physics
Table of Contents #. Date Title-Page – Page Number 29.April 14/15 Electrostatics 30.April 18/19 Electric Field 31.April 20/21 Electrostatics Problems 32.April 22/25 Circuits 33.April 26/28 Measuring Electricity 1
In: Label each diagram as series or parallel:
Objective: To understand Ohms law and measure: Simple Series Parallel circuits Success criteria: Calculate and measure current, voltage and resistance.
Amount of charge passing by every second: Current I=ΔQ Δt Measured in Amperes 1 Ampere= 1 Coulomb second
If a current of 45.0 mA exists in a metal wire, how much charge goes through in 20 minutes? How many electrons flow past a given cross section of the wire in 10.0 min? Sketch the direction of the current and the direction of the electrons motion.
Energy of each charge Electric potential V measured in Volts Energy charge
Voltage is like a pinball machine pushing the electrons out of the source into the circuit
Resistance to flow of electrons Resistance Measured in Ohms Ω
Resistance slows down the flow of electrons –Voltage used up –Light emitted –Heat emitted
How do you think the current would change if you increase the resistance in a circuit?
How do you think the current would change in a circuit if you increase the voltage into a circuit?
Ohms Law Georg Simon Ohm German physicist The relationship between current and voltage 1827
Ohms Law V=IR
A lightbulb has a resistance of 240 Ω when operating at a voltage of 120 V. What is the current in the bulb?
A toaster has a resistance of 10 kΩ. How much current flows through it at a voltage of 120V?
What is the resistance of a hair dryer if it runs at 120V with a current of 1 A?
What is the current of a lightning bolt that has a voltage of 10 million volts through air with a resistance of 2 KΩ?
Lab: Using a Multimeter Purpose: to measure circuits.
How to measure resistance voltage and current
Reading a Resistor
Measuring Voltage -Direct measurement of the push -Connect directly to the battery (or circuit if you want to measure change in voltage)
Measuring Resistance -Connect leads to resistor -Outside of a circuit
Measuring Current Must be a circuit Circuit must include the meter
Out: A hairdryer takes 1 amp of current at 120 V. What is its resistance?