Question

In the ionosphere electron execute 1. 4X10^6
revolutions in a second find the strength of
the magnetic flux density B in this region
(Mass of an electron =9.1X10^-31 kg. electronic
charge : 1.6×10^-19)​

Answer 1

Explanation:

$answer :$

0.5× 10^-5

Answer 2

Answer:

The strength of the magnetic flux density B in this region is 5×10⁻⁵T.

Explanation:

The force on a moving charge particle due to the magnetic field is given as;

$F=q(V\times B)$       (1)

Where,

F=force on the charged particle

q=charge

V=velocity executed by charge particle

B=magnetic field

we know that force can also be written at the product of mass and acceleration i.e.

$F=ma$       (2)

m= mass

a= acceleration

By equating equations (1) and (2) we get;

$ma=qVB$      (3)

Also,

$a=\frac{V^{2} }{R}$       (4)

R= radius

$V=R\times \omega$    (5)

By substituting equation (5) in (4) we get;

$a=\omega ^{2} \times R$     (6)

By substituting equations (6) and (5) in equation (3) we get;

$m\omega =qB$    (7)

The values given in the questions are;

frequency=1.4×10⁶Hz or revolution per second

mass of electron=9.1×10⁻³¹kg

charge on electron=1.6×10⁻¹⁹C

ω=2πf=2π×1.4×10⁶=8.792×10⁶ radian per second

By substituting the above values in equation (7) we get;

$9.1\times 10^-^3^1\times 8.792\times 10^6$=$1.6\times 10^-^1^9 \times B$

$B=5\times 10^-5 T$

Hence, the strength of the magnetic flux density B in this region is 5×10⁻⁵T.