to verify joule's law Flashcards
How was the current changed during the experiment?
a rheostat or variable resistor. by adjusting the rheostat, the resistance of the circuit is adjusted. the voltage is being divided between the thin metallic conductor’s resistance and the rheostat’s resistance, and when adjusted or varied, results to lowering/increasing the voltage.
Describe the procedure for this experiment.
fill the calorimeter with enough cold water to completely cover the heating coil. Transfer the water into a graduated cylinder to measure its volume. Transfer the water back to the calorimeter. use a thermometer to take an initial temperature reading. turn on the current and start the clock. allow the current to flow for 5 mins and record the value of current from the ammeter, making sure it is constant throughout the time interval by using the rheostat. at the end of the time interval, turn off the current and measure the highest temperature reached by the water. empty the water, replace with an equal volume of cold water and repeat with different values of current.
draw a suitable graph to verify joule’s law
change in temperature vs current squared
explain how the graph to verifies joule’s law
a straight line graph through the origin confirms that the rate at which heat is produced in a conductor is directly proportional to the square of the current
explain why the current was allowed to flow for a fixed length of time in each case.
to allow the measuring of the rise in temperature produced in a given time interval to confirms joule’s law(rate of heat production)
explain why a fixed mass of water was used.
the mass of water used is a variable in the experiment, and only one variable should be adjusted at a time
state errors and precautions for this experiment.
use a sensitive thermometer with a low specific heat capacity liquid.
cover and insulate the calorimeter and stir the water
replace water with an equal volume
parallax error with thermometer
