# The Sun Is Too Big!

An amateur astronomer wishes to estimate roughly the size of the sun using his crude telescope consisting of an objective lens of focal length $$200\text{ cm}$$ and an eyepiece of focal length $$10\text { cm}.$$ By adjusting the distance of the eyepiece from the objective, he obtains an image of the sun on a screen $$40\text{ cm}$$ behind the eyepiece.The diameter of the sun's image is measured to be $$6.0\text{ cm}.$$ Now, the question is what is the estimate of the sun's size, give that the average Earth-sun distance is $$1.5 \times 10^{11}\text{ m}.$$

Details and Assumptions:

• Enter your answer in scientific notation. For example $$3 \times 10^8$$ can be entered as $$3E+8.$$
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