Physics Current Electricity Level: High School
Ohm's lawAn 8.0 ohm, a 5.0 ohm and 20.0 ohm resistor are connected in series with a 24.0 V battery.
a) Calculate the equivalent resistance. In units of ohm.
b) What is the current in the circuit? In units of A.
c) What is the current in each resistor? In units of A.
Physics Current Electricity Level: High School
Ohm's lawA series combination of 2 resistors, 8.68 ohm and 2.40 ohm is connected to a 6.00 V battery.
a) Calculate the equivalent resistance of the circuit. In units of ohms.
b) Calculate the current in the circuit. Units of A.
c) What is the potential difference across the 8.68 ohm resistor? In units of V.
d) What is the potential difference across the 2.40 ohm resistor?
Physics Current Electricity Level: High School
Ohm's lawA 70 w bulb is plugged in a standard 110V outlet.
a) How much does it cost per month (31 days) to leave the light turned on? Assume electricity cost 4.93 cents/kW h. answer in units of dollars.
b) What is the resistance of the bulb? In units of ohm.
c) What is the current in the bulb? In units of mA.
Physics Current Electricity Level: High School
Ohm's lawA steam iron draws 4.0 A when connected to a potential difference of 116V.
a) What is the poer rating of this iron? In units of W.
b) How much energy is produced in 20 min? In units of J.
c) How much does it cost to run the iron for 20 min at $ 0.010/kW-h? Answer in dollars.
Physics Current Electricity Level: High School
Ohm's lawA 70.5 W bulb is connected to a 117 V source.
a) What is the current through the bulb? In units of A.
b) what is the resistance? In units of ohms.
c) A lamp dimmer puts a resistance in series with the bulb. What resistance would be needed to reduce the current to 0.32A? In units of ohms.
Physics Current Electricity Level: High School
Ohm's lawThe current in a certain resistor is 0.80 A when it is connected to a potential difference of 389V.
a) What is the current in this same resistor if the opening potential difference is 339 V? In units of A.
b) What is the current in the resistor when the potential difference is 113 V? In units of A.
Physics Current Electricity Level: High School
Ohm's lawThe damage caused by electrical shock depends on the current flowing through the body; 1mA can be felt and 5mA is painful. Above 15mA a person loses muscle control, and 70mA can be fatal. A person with dry skin has a resistance from one arm to the other arm of about 130000 ohms. When wet the resistance drops to about 5100 ohms.
a) What is the minimum voltage placed the arms that would produce a current that could be felt by a person with dry skin? Answer in units of V.
b)With the same electric potential what would be the current if the person has wet skin? Answer the units of mA.
c)What would be the minimum voltage that would produce a current that could be felt when the skin is wet? Answer in units of V.
Physics Current Electricity Level: High School
Ohm's law
A hair dryer draws a current of 9.3 A.
a) How long does it take for 7.2 x 10 to the third C of charge to pass thru the hair dryer? Answer in units of min.
b) How many electrons does this amount represent?
Physics Current Electricity Level: High School
Ohm's Law
The compressor on an air conditioner draws 133 a when it is started. The start up time is about 0.4 s. how much charge passes a cross – sectional area of the circuit on this time? Answer in units of c.
Physics Current Electricity Level: High School
EMF of a Battery
Complete the following statement . The electromotive force isa) the maximum potential difference between the terminals of a battery
b) the force that accelerates electrons through a wire when a battery is connected to it .
c) the force that accelerates protons through a wire when a battery is connected to it .
d) the maximum capacitance between the terminals of a battery .
e) the maximum electric potential energy stored within a battery .
Physics Current Electricity Level: High School
Combination of resistors
Find the equivalent resistance for all of the resistors in the figure at “click here” . The resistance is given in ohms .
Physics Current Electricity Level: High School
Combination of resistors
Find the current through each of resistors in the figure which is shown at “click here”
Physics Current Electricity Level: High School
Resistance
A 6.0 volt battery is connected in parallel with two identical lamps , each having a resistance of 24 ohms , Under these conditions , the resistance of the battery is negligible .a) Calculate the total resistance of the lamps ?
b) Calculate the current flowing through each lamp ?
c) Calculate the power consumption of each lamp .
d) What would happen to the current drawn from the battery if one of the lamps burnt out ?
e) Would it be hazardous if you stuck your finger in one of the lamp socket with the battery connected ? Why ?
Physics Current Electricity Level: High School
Resistance
a) Why are metals good conductors of electricity ?
b) What properties of a conductor would determine its electric resistance ?
c) Why does the resistance of a metallic conductor increase at higher temperature ?
Physics Current Electricity Level: High School
The heating element of a coffee maker operates at 120 volts and carries a current of 2 amps . Assuming that water absorbes all of the energy converted by the resistor , calculate how long its takes to heat 0.500 kg of water from room temperature (23.0 C) to boiling (100.0 C)a) Show that “T” (tau) = RC has units of time .
