Question

A uniform electric field, $\vec{ E }=-400 \sqrt{3} \hat{ y } NC ^{-1}$ 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 $2 \sqrt{10} \times 10^{6} \,ms ^{-1}$. 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 $\frac{ q }{ m }=10^{10} \,C\,kg ^{-1}$. Then

• A. the particle will hit $T$ if projected at an angle $45^{\circ}$ from the horizontal
• B. the particle will hit $T$ if projected either at an angle $30^{\circ}$ or $60^{\circ}$ from the horizontal
• C. time taken by the particle to hit T could be $\sqrt{\frac{5}{6}} \mu s$ as well as $\sqrt{\frac{5}{2}} \mu s$
• D. time taken by the particle to hit $T$ is $\sqrt{\frac{5}{3}} \mu s$

Answer 1

Answer: (B), (C)

the particle will hit $T$ if projected either at an angle $30^{\circ}$ or $60^{\circ}$ from the horizontal

Answer 2

The Correct Options are both B and C :
the particle will hit $T$ if projected either at an angle $30^{\circ}$ or $60^{\circ}$ from the horizontal.
time taken by the particle to hit T could be $\sqrt{\frac{5}{6}} \mu s$ as well as $\sqrt{\frac{5}{2}} \mu s$