A deuteron and an alpha particle having equal kinetic energy enter perpendicular into a magnetic field. Let r _ d and r _ α be their respective radii of circular path. The value of r _ d r _ α is equal to:

Correct answer: B. 2 r = (mv)/(qB) = 2mk qB r _ d r _ α = m _ d m _ α q _ α q _ d = (2)/(4) ((2)/(1)) = 2 Hence option ( 2 ) .

JEE Main 202120 JulyMorning Shift

JEE Main 2021 · 20 July · Morning Shift · Physics · Magnetic Effects of Current

A deuteron and an alpha particle having equal kinetic energy enter...

A deuteron and an alpha particle having equal kinetic energy enter perpendicular into a magnetic field. Let

{r}_{d}

and

{r}_{\alpha}

be their respective radii of circular path. The value of

\dfrac{{r}_{d}}{{r}_{\alpha}}

is equal to:

B. $\sqrt{2}$

r = \dfrac{mv}{qB} = \dfrac{\sqrt{2mk}}{qB}

\dfrac{{r}_{d}}{{r}_{\alpha}} = \sqrt{\dfrac{{m}_{d}}{{m}_{\alpha}}}\dfrac{{q}_{\alpha}}{{q}_{d}} = \sqrt{\dfrac{2}{4}}\left(\dfrac{2}{1}\right) = \sqrt{2}

Hence option

( 2 ) .