Questions
A particle of charge ‘q’ and mass ‘m’ starts moving from the origin under the action of an electric field and with a velocity . The speed of the particle will becomes after a time.
detailed solution
Correct option is D
E→ is parallel to B→ and V→ is perpendicular to both, therefore path of the particle is a helix with increasing pitch .Speed of particle at any time ‘t’ is given by V=Vx2+Vy2+Vz2here, Vy2+V22=V02 at all times because the yz components will remain same.Only the x component will increase due to electric field.After some time, it is given that V=2VoUsing, V=Vx2+Vy2+Vz2 ⇒2Vo=Vx2+Vo2 ⇒Vx = 3Vo Equation of kinematics, Vx=Ux+axt ⇒3V0=q2EoMt⇒t=3MV02qEo .Talk to our academic expert!
Similar Questions
A photon with energy of 4.9 eV ejects photoelectrons from tungsten. When the ejected electron enters a constant magnetic field of strength B = 2.5 mT at an angle of 60° with thee field direction, the maximum pitch of the helix described by the electron is found to be 2.7 mm. Find the work-function of the metal in electron-volt. Given that, specific charge of electron is 1.761011 C/ kg.
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