JEE Advanced2020PhysicsMotion in Two DimensionsActual
A uniform electric field, E → = - 400 3 j ^ N C - 1 is applied in a region. A charged particle of mass m carrying positive charge q is projected in this region with an initial speed of 2 10 × 10 6 m s - 1 . This particle is aimed to hit a target T , which is 5 m away from its entry point into the field as shown schematically in the figure. Take q m = 10 10 C kg - 1 . Then
Options
- Athe particle will hit T if projected at an angle 45 ° from the horizontal
- Bthe particle will hit T if projected either at an angle 30 ° or 60 ° from the horizontal
- Ctime taken by the particle to hit T could be 5 6 μ s as well as 5 2 μ s
- Dtime taken by the particle to hit T is 5 3 μ s
Correct answer
B. the particle will hit T if projected either at an angle 30 ° or 60 ° from the horizontal
Step-by-step solution
a y = E M = 4 3 × 10 12 m s 2 R = u 2 sin 2 θ a y sin 2 θ = R a y u 2 = 3 2 θ = 30 ° or 60 ° T = 2 u sin 30 ° a y or 2 u sin 60 ° a y = 5 6 μ s or 5 2 μ s