Answer: • Visible Light, Radio Waves
• Radio - 305-m , at Arecibo, Puerto Rico
Visible Light - 10.4m Mirror, Canary Island
Explanation:
The spectral window is simply the range of frequencies that are correctly measured. It should be noted that the signals that are outside the spectral window are folded when they show up in spectrum.
The two spectral windows through which electromagnetic radiation easily reaches the surface of earth are the visible light and the radio waves.
Given: The number = 0.0069 that has to be expressed in scientific notation
Concept: When we express any number in scientific notation then we shall consider two points.
(i) If we shift the decimal point from left to right after first (non-zero) digit then we count the number of shifted place of decimal and write them in terms of the negative power of 10. For example, 0.004789 = 4.789 ×10⁻³
(ii) If we shift the decimal point from right to left after first (non-zero) digit from the left end then we count the number of shifted place and write then in terms of the positive power of 10. For example, 4789.24 = 4.78924 ×10⁺³ = 4.78924 ×10³ Now, we shall convert the given number 0.0069 in scientific notation
0.0069 = 6.9 ×10⁻³ because we have shifted the decimal from left to right for three places that is after digit 6.
Hence, the last option 6.9 ×10⁻³ will be the correct option.
Answer:
a toy car speed is about 2.5 to 3.5 mph
There are two types of change in matter: physical change and chemical change. ... This is called the Law of Conservation of Matter. It states that matter can never be created or destroyed, only changed and rearranged.
Semi anthracite has the higest which is 29.5
