The provided text includes instructions for a lab experiment. Can you extract the steps of the experiment in a numbered list?

Steps of the Experiment:

1. Assemble the electrical circuit according to drawing L.9. Check the reliability of electrical contacts and the correct connection of the ammeter and voltmeter.
2. Collect the electrical circuit according to drawing L.9. Check the reliability of electrical contacts and the correct connection of the ammeter and voltmeter.
3. Verify the operation of the circuit with the key open and closed.
4. Measure the EMF of the power source.
5. Record the readings of the ammeter and voltmeter with the key closed for three positions of the rheostat slider and calculate r_пр. Record the measurement results in Table 13.
6. Calculate the absolute and relative errors in measuring the EMF and internal resistance of the power source using the accuracy class of the instruments. Record all data in Table 14.
7. Record the results of measuring the EMF and internal resistance of the power source: