The output power of a filter is 100 mW, when the signal frequency is 6 kHz. When the frequency is increased...

The output power of a filter is 100 mW, when the signal frequency is 6 kHz. When the frequency is increased to 25 kHz, the output power falls to 50 mW. What is the dB change in power ? (a) -3 dB (b) -5 dB (c) -7 dB (d) -2 dB
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The output power of a filter is 100 mW, when the signal frequency is 6 kHz. When the frequency is increased to 25 kHz, the output power falls to 50 mW. What is the dB change in power ? 

-3 dB 

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