A plant virus is a uniform cylindrical particle of `150A^(@)` in diameter and `5000A^(@)` long. The specific volume of the virus is 0.75 cm/g. If the virus is considered to be a single particle, the molecular weight is

Options

A. `7. 0 95 xx 10 ^(7)`
B. `70.95 xx 10 ^(7)`
C. `9.705 xx 10 ^(7)`
D. `7. 0 95 xx 10 ^(5)`

Answer

A

Explanation

Vomume of virus ` = pi r ^(2) l = (22)/(7) xx (150)/(2) xx (150)/(2) xx 10 ^(-16) xx 5000 xx 10 ^(-8) = 0. 884 xx 10 ^(-16) cm ^(3)`
`therefore` Mass of one virus ` = pi r ^(2) l = (22)/(7) xx (150)/(2) xx (150)/(2) xx 10 ^(-16) xx 5000 xx 10 ^(-8) = 0. 884 xx 10 ^(-16) cm ^(3)`
`therefore` molar mass of virus `=1.178 xx 10 ^(-16) xx 6. 023 xx 10 ^(23) = 7. 095 xx 10 ^(7)`