Answer:
Minimum time = 1.95x10^-4 s
Number of pulses = 5128.21 pulses/s
Explanation:
We have the speed of sound waves through human tissue with a value of 1540 m/s, to calculate the time it takes for the pulse to travel a distance of 30 cm (since the pulse will first travel a distance of 15 cm and then it will return another 15 cm to be detected by the equipment), therefore, the time between the two pulses will be equal to:
tminimum = 0.30 m/1540 m/s = 1.95x10^-4 s
To calculate the number of pulses, one second must be divided over the minimum time between the two pulses, as follows:
npulses = 1 s/1.95x10^-4 s = 5128.21 pulses/s
Answer:
C) It increases to 2.0 cm
Explanation:
In a double-slit diffraction experiment, the distance on the screen between two adjacent maxima is given by

where
is the wavelength of the wave
D is the distance of the screen from the slits
d is the separation between the slits
In this problem, the initial distance between adjacent maxima is 1.0 cm. Later, the slit separation is cut in a half, which means that the new slit separation is

Substituting into the equation, we find that the new separation between the maxima is

So, the distance increases by a factor 2: therefore, the new separation between the maxima will be 2.0 cm.
The Space Age began on October 4, 1957.
1. 
The wavelength of a wave is given by the formula

where
v is the speed of the wave
f is the frequency
For the electromagnetic wave in this problem,
is the frequency
is the speed of the wave
Substituting into the equation, we find

2. 
The angle of refraction can be found by using Snell's law:

where
is the refractive index of the first medium (air)
is the refractive index of the second medium (water)
is the angle of incidence in air
Solving the equation for
, we find the angle of refraction of the light ray in water:

the reflected light ray is 35° to the normal.
Explanation:
the light ray hitting the reflected surface is the incident ray, and forms an angle of incidence with the normal (the line perpendicular to the reflecting surface). The ray reflected fron the surface is called the reflected ray, and forms an angle of reflection.
since
the angle of incidence=angle of reflection
35° = 35°