Question

# 8- If the distance of a sound detector doubles (that is, the detector zooms out twice...

8- If the distance of a sound detector doubles (that is, the detector zooms out twice the original distance it is at), the sound level decreases by:

Select one: O

a. 1.4dB

b. 4.0cB

c. 6.0dB

d. 2.0dB

9- In an X-ray machine, electrons are subjected to electric fields of magnitude 6.0x105 N / C. Determine the acceleration the electrons experience is: Write your numerical result in the box provided.

If you need to write your result in scientific notation, you can write (for example):

7.12x10 15 I as 7.12e-15 J Remember to write the units next to the numerical value.

Notation to use: N- Newton m / s for meters between seconds m / s can be written as m / s2

10- Two point charges of +2.0 uC and -4.0 uC are separated by 1.5 cm. Determine how much is the magnitude of the electric force felt by the charges: Write your result in the box provided. If you need to write the result in scientific notation, you can write (for example) 4.5x1012 as 4.5e-12 Remember to write the units next to the numerical value, in the box.

12- A metallic object has a net charge of -3.8x10 C. How many excess electrons does the object have? Select one:

a)4.2 x 1014

b) 6.1 x 1013

c) 1.6 x 1014

d) 2.4 x 1013