Chp 1: Measurements

Question 1

Define systematic errors

Answer 1

Systematic errors result in all readings or measurements being always smaller or always larger than the true value by a fixed amount.

Question 1

Define Homogeneity of Equations

Answer 1

For an equation to be homogeneous, every term on both sides of the equal sign of the
equation should have the same units

Question 2

Define random errors

Answer 2

Random errors result in readings or measurements being scattered about a mean value with no fixed pattern

Question 3

Define accuracy

Answer 3

Accuracy is the closeness of a reading on an instrument to the true value of the quantity being measured

affected by systematic error.

find mean value

Question 4

Define precision

Answer 4

Precision of a measurement is how close the experimental values are to each other.

affected by random error

find range

Question 5

Define scalar

Answer 5

has magnitude only

Question 6

Define vector

Answer 6

magnitude and direction

Question 7

a homogeneous equation need not be physically correct. why?

Answer 7

1. may have incorrect dimensionless factor
2. missing or extra terms that have same unit

Question 8

name the 10 prefixes

Answer 8

1. pico (-12) p
2. nano (-9) n
3. micro (-6) u
4. milli (-3) m
5. centi (-2) c
6. deci (-1) d
7. kilo (3) k
8. mega (6) M
9. giga (9) G
10. tera (12) T

Question 9

Examples of systematic errors

Answer 9

1. due to apparatus (zero errors, poor calibration of instruments)
2. due to poor experimental technique (parallax error reduce by ensuring line of sight is perpendicular to the measuring scale)
3. due to external factors (background radiation cause reading to be consistently higher than its true reading)

Question 10

Example of random errors

Answer 10

1. due to inability of observer to repeat his action precisely (human reaction time reduced by taking average reading)
2. due to environmental conditions like pressure, temperature (reduced by taking average reading)
3. due to limited precision of instruments (reduced by taking stack of 10 identical __)

Question 11

3 types of uncertainty

Answer 11

1. absolute uncertainty (1sf)
2. fractional uncertainty (1/2sf)
3. percentage uncertainty (1/2sf)
   - fraction * %

Question 12

How does drawing a line of best fit help reduce random error?

Answer 12

The best fit line balances the deviations of the data points on either side of the line,
reducing the effects of random errors.

Question 13

Graphical depiction of:
Random error:
Systematic error:

Answer 13

Random error: the data points are scattered on both sides of the line of best fit.
Systematic error: the best fit line does not pass through the origin.