Number 2
4 marks · NormalAn engineer records the following readings for three components in a circuit:
| Component | Measurement |
|---|---|
| A | 4.5 × 10^{-2} |
| B | 7.3 × 10^{-1} |
| C | 2.8 × 10^1 |
Write the value of component B as an ordinary number.
Write the value of component C in standard form to 1 decimal place.
Calculate the product of component A and component C. Write your answer in standard form.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 0.73
(b) 2.8 × 10^1
(c) 1.26 × 10^0
Common mistakes: Incorrect decimal placement; Incorrect multiplication of indices
Show mark scheme and worked solution
Marking points
A1 (a) · 1 mark · Writes B as 0.73
A2 (b) · 1 mark · Writes C as 2.8 × 10^1 to 1 decimal place
M1 (c) · 1 mark · Multiplies A × C correctly using laws of indices
A3 (c) · 1 mark · Gives the answer 1.26 × 10^0 (or 1.26)
Worked solution
a) B = 7.3 × 10^{-1} = 0.73
b) C is already in standard form to 1 decimal place: 2.8 × 10^1
c) (4.5 × 10^{-2}) × (2.8 × 10^1) = (4.5 × 2.8) × 10^{-2 + 1} = 12.6 × 10^{-1} = 1.26 × 10^0