Hello there.
<span>Electromagnetic radiation is:
</span><span>A- energy that is electric and magnetic
</span>
The speed of the wave in the rod is

5044m/s
<h3>
What is sound wave?</h3>
A sound wave is the pattern of disruption brought on by the movement of energy moving through a medium as it propagates away from the source of the sound (such as air, water, or any other liquid or solid substance). Pressure waves are produced when an item vibrates, such as a ringing phone, and these waves are known as sound waves. The surrounding medium's particles are disturbed by the pressure wave, and those particles disrupt the particles next to them, and so on. Like ocean waves, the disturbance's pattern causes outward movement in all directions. Usually in all directions and with decreased intensity as it gets further away from the source, the wave transmits the sound energy through the medium.
To know more about sound wave, visit;
brainly.com/question/21995826
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Given Information:
Mass of elephant = m = 750 kg
Height = h = 14.3 m
time = t = 30 seconds
Required Information:
Power needed to lift elephant = P = ?
Answer:
Power needed to lift elephant ≈ 3507 watts
Explanation:
As we know power is given by
P = PE/t
Where PE is the potential energy and t is the time
Potential energy is given by
PE = mgh
Where m is the mass of elephant, g is the gravitational acceleration and h is the height to lift the elephant.
PE = 750*9.81*14.3
PE = 105212.25 Joules
Therefore, the required power to lift the elephant is
P = PE/t
P = 105212.25/30
P ≈ 3507 watts
Answer:
D. Frequency
Explanation:
The energy of an electromagnetic wave is proportional to frequency, mathematically it is expressed as;
E ∝ f
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ Js
The equation above can also be expanded to;

where;
c is speed of light = 3 x 10⁸ m/s
λ is the wavelength of the electromagnetic wave
Since the speed of light is constant, we can conclude that the energy of the electromagnetic wave is directly proportional to its frequency and inversely proportional to its wavelength.
Therefore, the correct option for direct proportionality is FREQUENCY