FG IV

Two sources, each one with a sound intensity of 90 dB, are acting in the same room. What is the resulting sound intensity?

A. 90 dB

B. 93 dB

C. 135 dB

D. 180 dB

 

 

FG III

At the earth’s surface, the average force exerted by a mass of 1 kg on its contact surface is

A. 9.8 N

B. 1 N

C. 0.98 N

D. 1 kg

 

 

FG II

If D is the diameter of a circle, what is its surface area?

A. π.D/2

B. π.D²

C. π.D²/2

D. π.D²/4