JEE PYQ: Thermal Properties Of Matter Question 5
Question 5 - 2021 (25 Feb 2021 Shift 1)
A proton, a deuteron and an $\alpha$ particle are moving with same momentum in a uniform magnetic field. The ratio of magnetic forces acting on them is ____ and their speed is ____ in the ratio.
(1) 2 : 1 : 1 and 4 : 2 : 1
(2) 1 : 2 : 4 and 2 : 1 : 1
(3) 1 : 2 : 4 and 1 : 1 : 2
(4) 4 : 2 : 1 and 2 : 1 : 1
Show Answer
Answer: (1)
Solution
$F = qvB = \frac{qpB}{m}$. For proton ($q, m$), deuteron ($q, 2m$), alpha ($2q, 4m$): $F_1 : F_2 : F_3 = 1 : \frac{1}{2} : \frac{1}{2} = 2:1:1$ and $v_1:v_2:v_3 = 1:\frac{1}{2}:\frac{1}{4} = 4:2:1$
BETA
