A device has a capacitance of 250nC. You are asked to decrease its capacitance to 50nC. How can you get it by connecting another capacitor with it?

To decrease the capacitance of a device from 250nF to 50nF, you can achieve this by connecting another capacitor in series with the existing one.

Reasoning:

When capacitors are connected in series, the total capacitance Ctotal is given by:

1/Ctotal=1/C1+1/C2

Where C is the capacitance of the original device (250nF), and C2 is the capacitance of the new capacitor you need to add.

You want the total capacitance to be 50nF, so:

1/50=1/250+1/C2

Solving for C2:

1/C2=1/50−1/250

1/C2=5/250−1/250

1/C2=4/250

Conclusion:

You would need to connect a capacitor with a capacitance of 62.5nF in series with the original 250nF capacitor to reduce the total capacitance to 50nF.

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