Physics · Forces and Motion
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A detector with a surface area of 1 square meter is placed 1 meter from an operating jackhammer. It measures the power of the jackhammer’s sounds as being 10−3 W and finds the intensity of the jackhammer.
- A
10 W/m2
- B
10-3 W/m2
- C
10-9 W/m2
- D
10-7 W/m2
- E
10-9 W/m2
Sound Intensity (SI) is defined as the power carried by sound waves per unit area in a direction perpendicular to that area. The units associated with SI is the watt per square metre (W/m2).
I = P/A =10-3/1
I = 10-3 Wm-2.
This option suggests the intensity is 10 W per square meter, which is incorrect because the power given is 10^-3 W.
This is the correct option. The intensity is calculated by dividing the power by the area, which is 10^-3 W/m2.
This option mistakenly suggests a much lower intensity than calculated. It doesn't match the power of 10^-3 W.
This option suggests an incorrect intensity level. The calculations based on given power and area do not support this.
This option suggests an incorrect intensity level. It is the same as Option C and incorrect for the same reasons.
Tagged under Physics · Forces and Motion · 2016