Calculate the minimum frequency of ultrasound (in Hz) that will allow you to see details as small as 0.193 mm in human tissue. (
1 answer:
Answer:
f = 7.97 x 10⁶ Hz = 7.97 MHz
Explanation:
The speed of a wave is given by the following formula:
where,
v = speed of the ultrasound wave through human tissue = 1540 m/s
f = frequency of ultrasound wave required = ?
λ = wavelength of ultrasound waves = smallest detail required = 0.193 mm
λ = 0.193 mm = 1.93 x 10⁻⁴ m
Therefore,
<u>f = 7.97 x 10⁶ Hz = 7.97 MHz</u>
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Answer:
3A is the larger of the two currents.
Explanation:
Let the currents in the two wires be I₁ and I₂
given:
Magnitude of the electric field, B = 4.0μT = 4.0×10⁻⁶T
Distance, R = 10cm = 0.1m
Ratio of the current = I₁ : I₂ = 3 : 1
Now, the magnitude of a magnetic field at a distance 'R' due to the current 'I' is given as
Where is the magnitude constant = 4π×10⁻⁷ H/m
Thus, the magnitude of a magnetic field due to I₁ will be
given,
B = B₁ - B₂ (since both the currents are in the same direction and parallel)
substituting the values of B, B₁ and B₂
we get
4.0×10⁻⁶T = -
or
4.0×10⁻⁶T =
also
⇒
substituting the values in the above equation we get
4.0×10⁻⁶T =
⇒
also
⇒
⇒
Hence, the larger of the two currents is 3A