00 SI Units

Question 1

Which of the following is NOT one of the SI base units?
a) Newton
b) Kelvin
c) Meter
d) Second

Answer 1

a) Newton

Newton is a derived unit, not a base SI unit. It’s derived from kg⋅m/s²

Question 2

What does the prefix ‘giga’ (G) represent?
a) 10³
b) 10⁶
c) 10⁹
d) 10¹²

Answer 2

c) 10⁹

The prefix ‘giga’ represents 10⁹ or 1,000,000,000

Question 3

How many Pascal (Pa) are in 2 GPa?
a) 2,000 Pa
b) 2,000,000 Pa
c) 2,000,000,000 Pa
d) 2,000,000,000,000 Pa

Answer 3

c) 2,000,000,000 Pa

G (giga) = 10⁹, so 2 GPa = 2 × 10⁹ Pa = 2,000,000,000 Pa

Question 4

How many seconds are there in 2.5 hours?
a) 150 seconds
b) 1,500 seconds
c) 9,000 seconds
d) 9,000,000 seconds

Answer 4

c) 9,000 seconds

1 hour = 3600 seconds
2.5 × 3600 = 9,000 seconds

Question 5

What is 25°C in Kelvin?
a) 248.15 K
b) 298.15 K
c) -248.15 K
d) 373.15 K

Answer 5

b) 298.15 K

To convert °C to K, add 273.15
25 + 273.15 = 298.15 K

Question 6

How many significant figures are there in 0.00340?
a) 2
b) 3
c) 5
d) 6

Answer 6

b) 3

Leading zeros are not significant
Only 3, 4, and 0 are significant digits

Question 7

What is 3.678 × 10⁵ rounded to 2 significant figures?
a) 3.7 × 10⁵
b) 3.6 × 10⁵
c) 3.68 × 10⁵
d) 4.0 × 10⁵

Answer 7

a) 3.7 × 10⁵

When rounding to 2 s.f., look at the third digit (7)
Since 7 ≥ 5, round up to 3.7

Question 8

Which of the following numbers is written correctly in standard form?
a) 15.6 × 10⁴
b) 1.56 × 10⁵
c) 0.156 × 10⁶
d) 156 × 10³

Answer 8

b) 1.56 × 10⁵

In standard form, the number must be between 1 and 10 multiplied by a power of 10
Only 1.56 × 10⁵ follows this rule

Question 9

Express a charge of 1 C
of charge in SI units.

Use the following equation to help you:

charge=current×time

Answer 9

The SI unit for current is amperes (A)
The SI unit for time is seconds (s)
Therefore: 1 C = 1 A × 1 s
Or written in SI base units: 1 C = 1 A⋅s

Question 10

How many bytes are there in 22 megabytes?

Answer 10

1 megabyte = 1,000,000 bytes Therefore, 22 megabytes = 22×1,000,000 = 22,000,000 bytes

Question 11

Convert room temperature (21°C) to kelvin

Answer 11

K = °C + 273.15
21°C + 273.15 = 294.15 K

Question 12

A ??? is equal to 1 x 10^12 watts
a) kilovolt
b) microjoule
c) terrawatt
d) terrajoule

Answer 12

c) terrawatt

Question 13

A ??? is equal to 1 x 10^9 watts
a) kilovolt
b) gigawatt
c) nanowatt
d) microwatt

Answer 13

b) gigawatt

Question 14

A ??? is equal to 1 x 10^6 watts
a) megawatt
b) millijoule
c) megavolt
d) terawatt

Answer 14

a) megawatt

Question 15

A ??? is equal to 1 x 10^3 watts
a) gigajoule
b) milliwatt
c) kilowatt
d) millimetre

Answer 15

c) kilowatt

Question 16

A ??? is equal to 1 x 10^-3 watts
a) kilojoule
b) nanowatt
c) microwatt
d) milliwatt

Answer 16

d) milliwatt

Question 17

A ??? is equal to 1 x 10^-6 watts
a) microwatt
b) kilometre
c) milliwatt
d) microvolt

Answer 17

a) microwatt

Question 18

A ??? is equal to 1 x 10^12 joules
a) terajoule
b) microvolt
c) millijoule
d) nanometre

Answer 18

a) terajoule

Question 19

A ??? is equal to 1 x 10^9 joules
a) millijoule
b) gigajoule
c) milliwatt
d) nanojoule

Answer 19

b) gigajoule

Question 20

A ??? is equal to 1x 10^6 joules
a) kilojoule
b) megajoule
c) nanojoule
d) millijoule

Answer 20

b) megajoule