Answer:
c. Your body is at rest but its inertia puts it in motion
Explanation:
Answer:
2.93 m (which agrees with answer "C" on the list)
Explanation:
Recall that the speed of the wave equals the product of the wave's length times its frequency. Therefore, the wavelength is going to be the quotient of the speed of the signal divided its frequency:
Wavelength = 2.997 10^8 / 1.023 10^8 = 2.93 m
<span>The energy source used to produce most of the electrical energy in the United States is Fossil fuels. Fossil fuels are generated over a long period of time by decomposition of dead flora and Fauna. Fossil fuels consists of three things- Coal, Petroleum and Natural Gas. Natural gas approx contributes 34%, Coal approx contributes 30% and Petroleum approx contributes 1% of total energy produced in US.</span>
A. 20m/s because the unit for velocity is m/s
Answer:
Option C
Explanation:
Given:
- Depth of tissue d = 12 cm
- frequency of ultrasound f = 1 MHz
- Input Intensity I_i = 1000 W/m^2
- attenuation coefficient soft tissue a = 0.54
Find:
- Out-put intensity at the required depth
Solution
- The amount of attenuation in (dB) with the progression of depth is given by:
Attenuation = a*f*d
Attenuation = 0.54*12*1
Attenuation = 6.48 dB
- The relation with attenuation and ratio of input and output intensity is given by:
Attenuation = 10*log_10 (I_i / I_o)
6.48 dB = 10*log_10 (I_i / I_o)
I_i / I_o = 10^(0.648)
I_o = 1000 / 10^(0.648)
I_o = 225 W/m^2
- Hence the answer is option C: I_o = 250 W/m^2
