Hi!! If someone wouldn't mind helping me with my physics extra credit questions, that'd be nice :)) Here they are: 1. Find the wavelength of the lowest frequency sound (f=20 Hz) that is audible to the human ear.
2. Find the wavelength of the highest frequency sound (f=20,000 Hz) that is audible to the human ear.
3. After seeing a lightning flash, you hear the clap of thunder 2 seconds later. How far away is the lightning?

1=> 17

meters

Explanation:

I assume here that the frequency that most humans can hear range from

20

Hz

to

20000

Hz

.

Wavelength is given by the equation:

λ

=

v

f

where:

λ

is the wavelength is meters

v

is the velocity in meters per second

f

is the frequency in hertz

From here, we see that wavelength is inversely proportional to frequency, and so to get the maximum wavelength, we need to have the smallest frequency that's hearable, which is

20

Hz

.

So, we get:

λ

=

340

m/s

20

Hz

=

340

m

s

−

1

20

s

−

1

(

∵

1

Hz

=

1

s

−

1

)

=

17

m

2=> Equivalently, for 20 kHz, which is the highest frequency most humans can hear, the wavelength would be 340 meters divided by 20,000, and that is 1.7 cm.

3=> After you see a flash of lightning, count the number of seconds until you hear the thunder. (Use the stop watch or count "One-Mississippi, Two-Mississippi, Three-Mississippi," etc.) For every 5 seconds the storm is one mile away. Divide the number of seconds you count by 5 to get the number of miles.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.