A patient is slowly pushed in a time of `10s` within the coils of the magnet of `MRI` machine where magnetic field is `B=2.0T`. If the patient's trunk is `0.8m` in circumference, the induced emf around the patient's trunk is

Options

A. `10.18xx10^(-3)V`
B. `10.18xx10^(-2)V`
C. `9.66xx10^(2)V`
D. `1.51xx10^(-2)V`

Answer

A

Explanation

`EMF`n induced
`e=(-dphi)/(dt)=-A(dB)/(dt)` `(:.phi=BA)`
It is given circumference of patient's trunk,
hence, `2pir=0.8m` (given )
`r=(0.8)/(2pi)m=(0.4)/(pi)m`
Area of cross section, `A=pir^(2)=pi((0.4)/(pi))^(2)=(0.16)/(pi)m^(2)`
Induced emf `|e|=(0.16)/(pi)xx(2)/(10)V~=10.18xx10^(2)V`