A particle having charge 'q' and mass 'm' is projected with velocity ( 4 i ^ − 6 j ^ + 3 k ^ ) m / sec from the origin in a region occupied by electric field ' E ' and magnetic field ' B ' such that B = B 0 j ^ and E = E 0 j ^ ( take m q E 0 = 2 ) . Find the time (in sec) when the magnitude of velocity of the charge particle becomes 5 5 m / sec . (neglect the gravity)

v y = u y + a y t : 0 = 6 − m q E 0 t 1 ⇒ t 1 = 3 s v x 2 + v y 2 + v z 2 = ( 5 5 ) 2 ⇒ 16 + v y 2 + 9 = 125 v y = 10 m / s 10 = m q E 0 t 2 ⇒ t 2 = 5 s t = t 1 + t 2 = 8 s Answer: 8.00

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Physics - Magnetism Question with Solution | TestHub

PhysicsMagnetismMotion analysis in electric & magnetic fieldMedium2 minQB

PhysicsMediumnumerical

A particle having charge 'q' and mass 'm' is projected with velocity $(4 \hat{i} - 6 \hat{j} + 3 \hat{k}) m / sec$ from the origin in a region occupied by electric field ' $E$ ' and magnetic field ' $B$ ' such that $B = B_{0} \hat{j}$ and $E = E_{0} \hat{j} ($ take $\frac{q E _{0}}{m} = 2)$ . Find the time (in sec) when the magnitude of velocity of the charge particle becomes $55 m / sec$ . (neglect the gravity)

Answer:

8.00

Solution:

$v_{y} = u_{y} + a_{y} t$ : $0 = 6 - \frac{q E _{0}}{m} t_{1} \Rightarrow t_{1} = 3 s$

$v_{x}^{2} + v_{y}^{2} + v_{z}^{2} = (55)^{2} \Rightarrow 16 + v_{y}^{2} + 9 = 125$

$v_{y} = 10 m / s$

$10 = \frac{q E _{0}}{m} t_{2} \Rightarrow t_{2} = 5 s$

$t = t_{1} + t_{2} = 8 s$

Answer: 8.00

Stream:JEESubject:PhysicsTopic:MagnetismSubtopic:Motion analysis in electric & magnetic field

⏱ 2mℹ️ Source: QB

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