D protons
k12 student here
Answer:
<em>380 kHz</em>
<em></em>
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:
Let's say the pitcher is angry or just has a really heavy hand while throwing this ball, and now you have to catch it, otherwise it's going to ram into your face. When you put your hands up just in time to catch this ball, this is called impulse, or commonly expressed as a reflex. Depending on what kind of ball is being thrown, such as a golf ball, baseball, basketball, beach-ball, rubber-ball, baseball, etc. ... the weight of the ball itself is going to impact how much it i going to hurt when you catch it without any hand protection. However, if you're catching, let's say a baseball, with a padded glove, it is not going to hurt as bad as catching the baseball bare handed, because the padded glove has enough padding in it to create a barrier between the skin of your hand and the palm of the glove.
Answer:
Option (A) and (F)
Explanation:
As the liquid cools down, it means the temperature decreases the density of the liquid increases in most o the cases.
Now the volume is inversely proportional to the density of substance so density increases.
Answer:
(a) 4.0334Ω
(b)parallel
Explanation:
for resistors connected in parallel;
Req =3.03Ω , R1 =12.18Ω
R2=1/0.2479
R2=4.0334Ω
(b)parallel connection is suitable for the desired total resistance. series connection can not be used to achieve a lower resistance as the equation for series connection is.
Req = R1+R2
