Final answer:
When the intensity of a 50-dB whistle is doubled, the new decibel level is approximately 53 dB, due to the nature of the logarithmic decibel scale. The correct option is a).
Step-by-step explanation:
The question asks about the new decibel level when the intensity of a sound measured at 50 dB is doubled. The formula to calculate the new decibel level when the intensity is doubled is:
dB_{new} = dB_{original} + 10 \cdot \log_{10}(2)
Since the logarithm (base 10) of 2 is approximately 0.30103, which can be rounded to 0.3, the calculation will be:
dB_{new} = 50 dB + 10 \cdot 0.3 = 50 dB + 3 dB = 53 dB
Therefore, when doubling the intensity of a 50-dB whistle, the new decibel level is approximately 53 dB. Option a) is the correct one.