How Many Influenza Viruses Land on You from a Cough?

[anf9292]

Homework Statement

A typical virus is a packet of protein and DNA (or RNA) and can be spherical in shape. The influenza A virus is a spherical virus that has a diameter of 85 nm. If the volume of saliva coughed onto you by your "friend" with the flu is 0.010 cm3 and 1/109 of that volume consists of viral particles, how many influenza viruses have just landed on you?

Homework Equations

V = 4/3 x pie x r^3

The Attempt at a Solution

I'm thinking that I should take half of 85nm which is 42.5nm and plugging it into the volume formula for a spherical. The volume of the whole spherical virus comes out to be 3.21E-5.

3.21E-5 / 0.010cm^3 = .00321

1/10^9 of .00321 = 3.11E-7 particles?

 

[Kurdt]

Its easier if you use nanometers in the original volume calculation. Secondly you would not divide the virus volume by the saliva volume, you need to do this the other way round. Thirdly I don't know if they want you take the spherical nature of the virus into account and assume spherical saliva which could make a big difference. You'll know what your teacher wants more than me.

 

[m2003]

Your calculations seem to be correct. However, it is important to note that the volume of a virus may vary and the number of virus particles in a given volume of saliva may also vary. Additionally, not all virus particles may be infectious, so the actual number of influenza viruses that have landed on you may be lower. It is also important to follow proper hygiene practices to prevent the spread of the virus.