Answer:
Once you've had chickenpox you can't again.
Explanation: the virus remains inactive in your nerve tissue. Although it's unlikely you will get chickenpox again, the virus may reactivate later in life and cause a related condition called shingles.
Answer:
reading would be 5.413 m.
Explanation:
Given:-
- The actual distance from ruler to an object is d = 24.0 m
- The adiabatic bulk modulus, B = 2.37 *10^9 Pa
- The density of seawater, ρ = 1025 kg/m^3
- The preset value of speed of sound in air, v_th = 343 m/s.
Find:-
Determine the distance reading that the ruler displays.
Solution:-
- We will first determine the actual speed of the sound ( v_a) in sea-water which can be determined from the following formula:
v_a = √ (B / ρ )
- Plug in the values in the relationship above and compute v_a:
v_a = √ ( 2.37 *10^9 / 1025 )
v_a = 1520.59038 m/s
- The time taken (t) for for the sound to travel from source(ruler) to an object which is d distance away.
d = v_a*t
t = d / v_a
t = 24.0 / 1520.59038
t = 0.01578 s
- The distance reading on the ruler would be preset speed (v_th) of sound in air multiplied by the time taken(t).
reading = v_th*t
reading = (343)*(0.01578)
= 5.413 m
Answer:
0.000000002 m=2.0*10⁻⁹ m
Explanation:
Scientific notation allows us to write very large or very small numbers in abbreviated form. This notation simply consists of multiplying by a power of base 10 with a positive or negative exponent.
A number written in scientific notation has the form:
a*10ⁿ
where:
- the coefficient a has a value such that 1 ≤ a <10
- n is an integer. Represents the number of times the decimal point is shifted. It is always a whole number, positive if it is shifted to the left, negative if it is shifted to the right.
So to write the number 0.000000002 in scientific notation, the following steps are performed:
- The decimal point is moved to the right as many spaces until it reaches the right of the first digit.
- This number is then written, which will be the coefficient a in the expression of the previous product. So a=2.0
- The base 10 is written with the exponent equal to the number of spaces that the comma moves. So n=9. But this is a negative number because the comma shifts to the right.
So, you get: <u><em>0.000000002 m=2.0*10⁻⁹ m</em></u>
The frequency of the human ear canal is 2.92 kHz.
Explanation:
As the ear canal is like a tube with open at one end, the wavelength of sound passing through this tube will propagate 4 times its length of the tube. So wavelength of the sound wave will be equal to four times the length of the tube. Then the frequency can be easily determined by finding the ratio of velocity of sound to wavelength. As the velocity of sound is given as 339 m/s, then the wavelength of the sound wave propagating through the ear canal is
Wavelength=4*Length of the ear canal
As length of the ear canal is given as 2.9 cm, it should be converted into meter as follows:
Then the frequency is determined as
f=c/λ=339/0.116=2922 Hz=2.92 kHz.
So, the frequency of the human ear canal is 2.92 kHz.
