One need to design a filter with cut off frequency 330 Hz. Which of the following resistor and capacitor combination is correct. R = 1K Ohm C=0.48 micro farad R = 10K Ohm C=0.48 micro farad R = 2K Ohm C=0.047 micro farad R = 20K Ohm C=0.047 micro farad

The cut-off frequency (f_c) of a first order RC (Resistor-Capacitor) filter can be calculated using the formula:

f_c = 1 / (2πRC)

where R is the resistance in ohms (Ω), C is the capacitance in farads (F), and π is approximately 3.14159.

Let's calculate the cut-off frequency for each given R and C combination:

1. For R = 1K Ohm and C = 0.48 micro farad:

   f_c = 1 / (2π * 1K * 0.48 * 10^-6) = 331.57 Hz

2. For R = 10K Ohm and C = 0.48 micro farad:

   f_c = 1 / (2π * 10K * 0.48 * 10^-6) = 33.16 Hz

3. For R = 2K Ohm and C = 0.047 micro farad:

   f_c = 1 / (2π * 2K * 0.047 * 10^-6) = 1691.5 Hz

4. For R = 20K Ohm and C = 0.047 micro farad:

   f_c = 1 / (2π * 20K * 0.047 * 10^-6) = 169.15 Hz

From the above calculations, the combination of R = 1K Ohm and C = 0.48 micro farad gives the cut-off frequency closest to 330 Hz. Therefore, this is the correct resistor and capacitor combination for designing a filter with a cut-off frequency of 330 Hz.