Question

An electron accelerated through potential difference 'V' passes through a uniform transverse magnetic field and experiences a force 'F'. If the accelerating potential in increased to '2V', the electron in the same magnetic field will experience a force ____________.

विकल्प

• F

• 3F

• `"F"/2`

• `sqrt2  "F"`

Answer 1

An electron accelerated through potential difference 'V' passes through a uniform transverse magnetic field and experiences a force 'F'. If the accelerating potential in increased to '2V', the electron in the same magnetic field will experience a force `sqrt2  "F"`.

Explanation:

Kinetic energy k₁ = eV and k₂ = 2eV

`therefore "k"_2/"k"_2 = 2  therefore "v"_1 and "v"_2  "are the velocities in the two cases then"`

`"k"_2/"k"_1 = "v"_2^2/"v"_1^2`

`therefore "v"_2/"v"_1 = sqrt("k"_2/"k"_1) = sqrt2`

`"F"_2/"F"_1 = ("ev"_2 "B")/("ev"_1 "B") = "v"_2/"v"_1 = sqrt2`

`therefore "F"_2 = sqrt2  "F"_1 = sqrt2  "F"`