SI BASE UNITS

Question 1

the time required for 9 192 631 770 cycles of microwave radiation in cesium-133 atoms.

Answer 1

Second

Question 2

the distance traveled by light in a vacuum in
1/299 792 458 second

Answer 2

Meter

Question 3

redefined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 ✕ 10−34 when expressed in the unit J s, which is equal to kg m2 s−1.

Answer 3

Kilogram

Question 4

defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 ✕ 10−19 when expressed in the unit C, equivalent to the product of current (A) and time (s).

Answer 4

Ampere

Question 5

defined by taking the fixed numerical value Boltzmann constant k to be 1.380 649 ✕ 10−23 when expressed in the unit J K−1, equivalent to kg m2 s-2 K-1.

Answer 5

Kelvin

Question 6

one mole contains exactly 6.022 140 76 ✕ 1023 elementary entities, which is the fixed value of the Avogadro constant, NA when expressed in the unit mol−1.

Answer 6

Mole

Question 7

defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation with frequency of 540 ✕ 1012 Hz, Kcd, to be 683 when expressed in the unit lm W-1, equal to cd sr W-1 or cd sr kg-1 m-2 s3.

Answer 7

Candela