Answer:
The focal lenth (F) =+10.0cm
Explanation:
The formular for combined focal length (F) is given as;

In this question,
F1 = 20cm
F2 = -30cm
Plugging the values into the formuar above,

![1/f = 0.05 - 0.033[tex]1/f = -0.017f = [tex]1/ -0.017](https://tex.z-dn.net/?f=1%2Ff%20%3D%200.05%20-%200.033%3C%2Fp%3E%3Cp%3E%5Btex%5D1%2Ff%20%3D%20-0.017%3C%2Fp%3E%3Cp%3Ef%20%3D%20%5Btex%5D1%2F%20-0.017)
f = 58.82cm
i.e. the combination behaves as a converging lens (because of the postive sign) of focal length 58.82cm .
Big Bang is a theory that, as stated above, has grown to become widely acceptable scientific explanation of the origin of things. Research would say that according to this theory, the Earth originated billion years ago through an explosive of a highly energized point.
Through this explosion, the elements were formed. However, only the lightest of the elements including hydrogen and helium, with traces of lithium and beryllium. From the choices, the answer would have to be the second choice, helium.
Answer: B. helium
Answer: The five major fields of environmental science are social sciences, geosciences, environmental chemistry, ecology, and atmospheric sciences.
Explanation:
14.136 J as shown on the photo with two thought processes but overall same calculation
Sound must travel through a medium/body. Space is a vacuum so there is no medium/body for sound to travel through, so there is no sound.