/ Class 8 · Chapter 2: Exponents (Powers) Function Lab

Speed of Light in Scientific Notation

Convert 300,000 km/s into a compact number using powers of 10.

Equation
y = 1 * 10^x
Graph
0246-5M5M15M25M35M45Mg2xy
Table
xy
01
110
2100
31000
410000
5100000
61000000

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Selina ICSE: Exponents (Powers)

What this lesson covers

What you do

You shape the function y = a * 10^x and watch the graph answer.

Challenges to clear

  • Set a = 3. Scan the powers of ten: 300,000 sits at x = 5 — the speed of light is 3 × 10⁵ km/s.
  • One power less is ten times smaller: x = 4 shows 30,000.
  • A new measurement: 700,000. The digit part is 7 — slide a there.
  • Now shift the powers so x = 3 lands on 700,000. In standard form that is 7 × 10⁵, so the shift c is 2.

Check yourself

Why is 300,000 written as 3 * 10^5 and not 30 * 10^4?

If the speed of sound is approximately 340 m/s, which of the following is the correct scientific notation?

  • Because in scientific notation, the first number (coefficient) must be greater than or equal to 1 and less than 10. — correct
  • Because 30 * 10^4 equals 300,000, so both are correct.
  • Because 10^5 is a larger number than 10^4.
  • Because we always start with the digit 3.
  • 3.4 * 10^2 — correct
  • 34 * 10^1
  • 0.34 * 10^3
  • 340 * 10^0
Hold to talk

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