Answer:
z = 0.8 (approx)
Explanation:
given,
Amplitude of 1 GHz incident wave in air = 20 V/m
Water has,
μr = 1
at 1 GHz, r = 80 and σ = 1 S/m.
depth of water when amplitude is down to 1 μV/m
Intrinsic impedance of air = 120 π Ω
Intrinsic impedance of water = 
Using equation to solve the problem

E(z) is the amplitude under water at z depth
E_o is the amplitude of wave on the surface of water
z is the depth under water



now ,


taking ln both side
21.07 x z = 16.81
z = 0.797
z = 0.8 (approx)
The correct answers are: Options 2,4 and, 5
2)He solved Ptolemy’s model by proving elliptical orbits.
4)He determined that planets move faster when closer to the Sun.
5)He discovered laws of planetary motion.
<span>The observation or measurement of physical properties of matter does not change its composition or its chemical nature. Other examples of physical properties include the infrared spectrum, attraction or repulsion to magnets, viscosity and opacity.</span>
Inertness, especially with regard to effort, motion, action, and the like; inactivity; sluggishness.
Answer:
A.Moving electric charges (electrons in a circuit) creates a magnetic field and
a magnetic field can cause an electric charge to move (electricity).
Explanation: