Answer:
Explanation:
Intensity of sound = sound energy emitted by source / 4 π d² , where d is distance of the source .
A )
Intensity of sound at 1 m distance = 60 /4 π d²
d = 1 m
Intensity of sound at 1 m distance = 60 /(4 π 1²)
= 4.78 W m⁻² s⁻¹
B )
Intensity of sound at 1.5 m distance = 60 /4 π d²
d = 1.5 m
Intensity of sound at 1 m distance = 60 /(4 π 1.5²)
= 2.12 W m⁻² s⁻¹
C )
Intensity of sound due to 4 speakers at 1.5 m distance = 4 x 60 /4 π d²
d = 1.5 m
= 4 x 60 /(4 π 1.5²)
= 8.48 W m⁻² s⁻¹
D )
Intensity of sound due to .06 W speaker must be 10⁻¹² W s ⁻² . Let the distance be d .
.06 /4 π d² = 10⁻¹²
d² = .06 /4 π 10⁻¹²
d = 6.9 x 10⁴ m .
Answer:
6 centimeter = 60 millimeter
Explanation:
1 meter = 100 centimeter
1 centimeter = 0.01 meter
Thus, 6 × 1 centimeter = 6 × 0.01 meter
6 centimeter = 0.06 meter
Hence, first option is wrong.
1 centimeter = 10 millimeter
6 × 1 centimeter = 6 × 10 millimeter
6 centimeter = 60 millimeter
Thus, third option is correct.
I hope this will help you
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