Answer:The frequency of the echo is slightly decreased
Explanation:
Given
speed of boat 
cliff is 
away
when boat is still , suppose t is the time taken by the echo to reach observer on the boat
But as soon as boat starts moving the distance between cliff and boat decreasing and time for echo to reach observer also decreases
and we know 
therefore frequency of the echo slightly decreased.
Answer:
ε = 2 V/cm
Explanation:
To calculate the mobility inside this bar, we just need to apply the expression that let us determine the mobility. This expression is the following:
ε = ΔV / L
Where:
ε: Hole mobility inside the bar
ΔV: voltage applied in the bar
L: Length of the bar
We already have the voltage and the length so replacing in the above expression we have:
ε = 2 V / 1 cm
<h2>
ε = 2 V/cm</h2><h2>
</h2>
The data of the speed can be used for further calculations, but in this part its not necessary.
Hope this helps
Answer:
a) θ₁ = 23.14 °
, b) θ₂ = 51.81 °
Explanation:
An address network is described by the expression
d sin θ = m λ
Where is the distance between lines, λ is the wavelength and m is the order of the spectrum
The distance between one lines, we can find used a rule of proportions
d = 1/600
d = 1.67 10⁻³ mm
d = 1-67 10⁻³ m
Let's calculate the angle
sin θ = m λ / d
θ = sin⁻¹ (m λ / d)
First order
θ₁ = sin⁻¹ (1 6.5628 10⁻⁷ / 1.67 10⁻⁶)
θ₁ = sin⁻¹ (3.93 10⁻¹)
θ₁ = 23.14 °
Second order
θ₂ = sin⁻¹ (2 6.5628 10⁻⁷ / 1.67 10⁻⁶)
θ₂ = sin⁻¹ (0.786)
θ₂ = 51.81 °
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Below are the choices and the answer is <span>B.
</span>a.) Models can be changed by scientists who are more famous than previous scientists.
<span>b.) As technology advances, new experiments often expose problems in accepted theories. </span>
<span>c.) Scientists tend to value new theories because they are more exciting. </span>
<span>d.) A newer theory is more valid because it uses more mathematics. </span>
In a surface wave (like water) the water goes up and down, but the wave travels across (parallel to) the surface.
