Answer:
<em>380 kHz</em>
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Explanation:
The speed of sound is taken as 1500 m/s
The length of the fetus is 1.6 cm long
The condition is that the wavelength used must be at most 1/4 of the size of the object that is to be imaged.
For this 1.6 cm baby, the wavelength must not exceed
λ = 
of 1.6 cm = x 1.6 cm = 0.4 cm =
0.4 cm = 0.004 m this is the wavelength of the required ultrasonic sound.
we know that
v = λf
where v is the speed of a wave
λ is the wavelength of the wave
f is the frequency of the wave
f = v/λ
substituting values, we have
f = 1500/0.004 = 375000 Hz
==> 375000/1000 = 375 kHz ≅ <em>380 kHz</em>
Answer:
reduce passive stiffness and increase range of movement during exercise.
Explanation:
stretching performed as part of a warm up prior to exercise is thought to reduce passive stiffness and increase range of movement during exercise. in general it appears that is static stretching is most beneficial for athletes requiring flexibility for their sports.
There are four quantum numbers:
1) Principal quantum number which tells the shell in which the electron is and is an integer number starting from 1. Both of these electrons are in the same shell, the third.
2) Azimuthal quantum number which tells the subshell of the electron. This has a value of an integer starting from 0, 0 being the s orbital. The first electron is in the d orbital due to the number being 2 and the second is in the p orbital due to the number being 1.
3) Magnetic quantum number tells the orbital within the subshell. The first electron is in the -1 orbital of the d subshell (which has values from -2 to 2) and the second is in the -1 orbital of the p subshell (which has values from -1 to 1).
4) Spin quantum number which specifies the spin on the electron, both of the electrons have the same spin.
