Working as a physicist

Question 1

terra

Answer 1

(T) x10^12 (a thousand billion)

Question 2

Giga

Answer 2

(G) x10^9 (a billion)

Question 3

Mega

Answer 3

(M) x10^6 (a million)

Question 4

Kilo

Answer 4

(k) x10^3 (a thousand)

Question 5

milli

Answer 5

(m) x10^-3 (a thousandth)

Question 6

micro

Answer 6

(u) x10^-6 (a millionth)

Question 7

nano

Answer 7

(n) x10^-9 (a billionth)

Question 8

pico

Answer 8

(p) x10^-12 ( a thousand billionth)

Question 9

femto

Answer 9

(f) x10^-15

Question 10

Area of rectangle

Answer 10

base x height (m^2)

Question 11

area of square

Answer 11

base x height

Question 12

circle

Answer 12

pi x radius^2

Question 13

Volume of a cuboid

Answer 13

base x height x depth (m^3)

Question 14

volume of cylinder

Answer 14

height x (pi x radius^2)

Question 15

volume of a sphere

Answer 15

4/3 x pi x radius^3

Question 16

definition of resolution

Answer 16

the smallest measuring interval and the source of uncertainty in a single reading

Question 17

uncertainty in measurements?

Answer 17

• physical quantities cannot be measured exactly with any instrument
  -there is always an uncertainty in the reading
  -this is quoted as a plus or minus reading
  _
  +1mm on a meter ruler
  _
  + 20mv on a digital voltmeter

Question 18

what are the two types of uncertainty

Answer 18

systematic error
random error

Question 19

what is systematic error?

Answer 19

a fault with the equipment
these errors are usually in one direction and can be compensated for

Question 20

what is random error?

Answer 20

usually due to human error in taking readings
these are always given as plus or minus uncertainties

Question 21

definition of uncertainty

Answer 21

the interval within the true value can be considered to lie with a given level of confidence or probability. All measurements will have some uncertainty about the result , this will come from the variation in the data obtained and be subject to systematic or random effects. This can be estimated by considering the instruments and the method.

Question 22

definition of error

Answer 22

the difference between the measurement result and the true value if a true value is thought to exist. This is not a mistake in the measurement. the error can be due to both systematic and random effects and an error of unknown size is a source of uncertainty.

Question 23

what is the absolute uncertainty

Answer 23

the absolute value for an uncertainty has to be estimated
- metre ruler has an absolute uncertainty of +- 0.5mm
- use half of the resolution

Question 24

how to calculate absolute uncertainty

Answer 24

• half the resolution
• if there’s more than one result then you get the range of the results and half of it for the uncertainty and use mean for reading

Question 25

what is the percentage uncertainty

Answer 25

the uncertainty of a reading as a percentage of the actual reading taken
percentage uncertainty= +- absolute uncertainty/actual reading x 100