Q12E - University Physics with Modern Physics

Question

(a) The recommended daily allowance (RDA) of the trace metal magnesium is $410$ mg/day for males. Express this quantity in mg/day. (b) For adults, the RDA of the amino acid lysine is $12$ mg per kg of body weight. How many grams per day should a $75$-kg adult receive? (c) A typical multivitamin tablet can contain $2.0$ mg of vitamin B$2$ (riboflavin), and the RDA is $0.0030$ g/day. How many such tablets should a person take each day to get the proper amount of this vitamin, if he gets none from other sources? (d) The RDA for the trace element selenium is$0.000070$g/day. Express this dose in mg/day.

Step-by-Step Solution

Answer

After the calculation as per given problem a $75$ Kg weighed adult can consume $900$mg or $0.900$grams of Lysine.

Calculation daily trace

$410$mg/day

=$410\times 1000=410000$

consumption by 75 Kg weighed adult

(b)

$1000mg=1 gram$

So, hypothetically if someone weighed $1$Kg they would need $12$mg of Lysine daily.

That means , a $75$ Kg adult would need $900$mg lysine, which is$0.900$grams.

Calculation of number of tablets

( c)

No of tablets =$0.003/0.002=1.5$ tablets

Therefore, he should take $2$ tablets.

Conversion

$0.000070$g/day=$0.070$mg/day(conversion g to mg )