Answer:
<em>The wavelength of water = 571.43 nm</em>
Explanation:
Refractive index of water = wave length of light in air/wave length of light in water
R.d = λ₁/λ₂.................. Equation 1
making λ₂ the subject of equation 1
λ₂ = λ₁/R.d...................... Equation 2
R.d = refractive index of water , λ₁ = wave length of light in air, λ₂ = wave length of light in water
<em>Given: R.d = 1.33, λ₁ = 760nm</em>
<em>Substituting these values into equation 2</em>
λ₂ = 760/1.33
<em>λ₂ = 571.43 nm</em>
<em>Therefore the wavelength of water = 571.43 nm</em>
8. In soft magnetic materials such as iron, what happens when an external magnetic field is removed?
a. The domain alignment persists.
b. The orientation of domains fluctuates.
c. The material becomes a hard magnetic material.
d. The orientation of domains changes, and the material returns to an unmagnetized state.
9. According to Lenz’s law, if the applied magnetic field changes,
a. the induced field attempts to keep the total field strength constant.
b. the induced field attempts to increase the total field strength.
c. the induced field attempts to decrease the total field strength.
d. the induced field attempts to oscillate about an equilibrium value.
10. The direction of the force on a current-carrying wire in an external magnetic field is
a. perpendicular to the current only.
b. perpendicular to the magnetic field only.
c. perpendicular to the current and to the magnetic field.
d. parallel to the current and to the magnetic field
1. Frequency: 
The frequency of a light wave is given by:
where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength
Substituting into the equation, we find the frequency:
2. Period: 
The period of a wave is equal to the reciprocal of the frequency:
The frequency of this light wave is (found in the previous exercise), so the period is:
displ = velocity x time
25 x 3.2 = 75+5 km north.
This question would be false
