<span>The statement, Sunlight is a
form of electromagnetic energy, is true. The answer is letter A. Electromagnetic
energy is a form of radiant energy that released by electromagnetic radiation. One
example of an electromagnetic radiation is the visible light. And visible light
can be radio waves, infrared light and X - rays. The rays of the sun are a form
of visible light. It has an electromagnetic radiation of UV (ultra violet)
rays. That is why the radiation at day is greater than at day due to sun’s
rays. </span>
Momentum is mass in motion and only applies to objects in motion. It's a term that describes a relationship between the mass and velocity of an object, and we can see this when it is written in equation form, p = mv, where p is momentum, m is mass in kg and v is velocity in m/s.
efficiency = (useful energy transferred ÷ energy supplied) × 100
It's easy to use this formula, but we have to know both the useful energy and the energy supplied. The drawing doesn't tell us the useful energy, so we have to find a clever way to figure it out. I see two ways to do it:
<u>Way #1:</u>
We all know about the law of conservation of energy. So we know that the total energy coming out must be 250J, because that's how much energy is going in. The wasted energy is 75J, so the rest of the 250J must be the useful energy . . . (250J - 75J) = 175J useful energy.
(useful energy) / (energy supplied) = (175J) / (250J) = <em>70% efficiency</em>
================================
<u>Way #2: </u>
How much of the energy is wasted ? . . . 75J wasted
What percentage of the Input is that 75J ? . . . 75/250 = 30% wasted
30% of the input energy is wasted. That leaves the other <em>70%</em> to be useful energy.