Q124 / 180 · AIIMS 2006 · Physics

An amplifier has a voltage gain $A_V=1000$. The voltage gain in $\mathrm{dB}$ is

A
$30 \mathrm{~dB}$
Correct answer
B
$60 \mathrm{~dB}$
C
$3 \mathrm{~dB}$
D
$20 \mathrm{~dB}$.

Solution

$$ \begin{aligned} \text { : Voltage gain in } \mathrm{dB} & =20 \log _{10} A_V \\ & =20 \log _{10}(1000)=60 \mathrm{~dB} . \end{aligned} $$

Hence, the correct answer is option: 'B'.

More Waves and Sound Questions

If equation of sound wave is , then its wavelength will be2002Properties of Sound Waves
A string wave equation is given and mass density is . Then find the tension in the string.26 May, 2019Basics of Mechanical Waves
Two sources of sound and are moving towards and away from a stationary observer with same speed respectively. Observer detects 3 beats per s25 May, 2019Doppler’s Effect
If speed of sound in air in , then find the number of overtones present in an open organ pipe of length whose frequency25 May, 2019Organ Pipe (Vibration of Air Column)
Assertion : The speed of sound in a gas is not affected by change in pressure provided the temperature of the gas remains constant. Reason :27 May, 2018Speed of Sound Waves
Assertion : Resonance is a special case of forced vibrations in which the natural frequency of vibration of the body is the same as the impr27 May, 2018Organ Pipe (Vibration of Air Column)