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The distance between planets is measured in Astronomical Units (AU).
\(1\ \text{AU}\ \approx 1.496\times 10^8\) kilometres.
Given Venus is approximately 0.7 AU from Earth, calculate this distance in kilometres giving your answer in scientific notation, correct to 3 significant figures. (2 marks)
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\(1.03\times 10^8\ \text{(3 sig. fig.)}\)
| \(\text{Distance}\) | \(=0.7\times \left(1.496\times 10^8\right)\) |
| \(=102\,830\,000\) | |
| \(=1.0283\times 10^8\) | |
| \(=1.03\times 10^8\ \text{(3 sig. fig.)}\) |
The area `(A)` of a circle is given by the formula `A=\pi r^2`, where `r` is the radius.
What is the value of `A`, correct to three significant figures, if `r=3.55` ?
`B`
| `A` | `=pi\r^2` | |
| `=pi xx3.55^2` | ||
| `=39.591…` | ||
| `=39.6\ \ text{(3 sig fig)}` |
`=>B`
Suppose `a=b/7`, where `b=22.`
What is the value of `a`, correct to three significant figures?
`A`
`a=b/7=22/7=3.1428…`
`3.1428 = 3.14\ text{(to 3 sig fig)}`
`=> A`
What is 0.002073 expressed in standard form with two significant figures?
`D`
| `0.002073` | `= 2.073 xx 10^(-3)` | |
| `=2.1 xx 10^(-3)\ \ \ text{(to 2 sig fig)}` |
`=> D`
What is 208.345 correct to two significant figures?
`B`
`208.345 = 210\ (2\ text(sig. fig.))`
`=> B`
What is 1 560 200 km written in standard form correct to two significant figures?
`D`
♦♦ Mean mark 30%.
COMMENT: Incredibly, the first MC question in 2015 had the lowest mean mark of all MC questions in the exam!
`1\ 560\ 200`
`= 1.5602 xx 10^6`
`= 1.6 xx 10^6\ text(km)\ \ \ text{(2 sig fig)}`
`=> D`