First of all, it's great that you are building a circuit for a project and seeking help to understand important factors such as current, voltage drop, and resistance. These are crucial components in any electrical circuit and understanding them will help you troubleshoot and optimize your circuit.
To calculate the current in your circuit, you can use Ohm's Law, which states that current (I) is equal to the voltage (V) divided by the resistance (R). In this case, since your circuit is wired in series, the current will be the same throughout the circuit. Therefore, the current can be calculated by dividing the voltage of your power supply (12V) by the total resistance of the circuit. This includes the 1kΩ resistor and the resistance of the 85 LEDs. To calculate the resistance of the LEDs, you will need to know their individual resistance values and then add them together.
Once you have calculated the current, you can use Ohm's Law again to calculate the voltage drop across the 1kΩ resistor. This can be done by multiplying the current by the resistance of the resistor. This will give you the voltage drop across the resistor, which can then be subtracted from the power supply voltage to determine the voltage drop across the LEDs.
Finally, to calculate the total resistance of your circuit, you will need to add the resistance of the 1kΩ resistor to the resistance of the 85 LEDs. This will give you the total resistance that the power supply is pushing against.
I hope this helps you understand how to calculate the current, voltage drop, and resistance in your circuit. Keep in mind that these calculations are theoretical and may differ slightly from the actual values due to factors such as temperature and tolerance of components. It is always a good idea to double-check your calculations and measure the actual values in your circuit to ensure accuracy. Good luck with your project!