Practice portal › Electric Charge and Properties › Motion of a Charge in an Electric Field

An electron is made to enter symmetrically between two parallel and equally but oppositely charged metal plates, each of 10 cm length. The electron emerges out of the electric field region with a horizontal component of velocity 10⁶ m s⁻¹. If the magnitude of the electric field between the plates is 9.1 V cm⁻¹, then the vertical component of velocity of the electron is (mass of electron =9.1×10⁻³¹ kg and charge of electron =1.6×10⁻¹⁹ C)

Asked in JEE Main 22nd Jan 1st Shift 2025 · Deflection and projectile motion

Answer: (1) 16×10⁶ m s⁻¹

Step-by-step solution

The field is transverse, so the horizontal motion is uniform: time inside the plates t=L/(vₓ)=(0.10)/(10⁶)=10⁻⁷ s.

Convert the field: E=9.1 V cm⁻¹=910 V m⁻¹.

Transverse acceleration a=(eE)/m=(1.6×10⁻¹⁹×910)/(9.1×10⁻³¹)=1.6×10¹⁴ m s⁻².

v_y=at=1.6×10¹⁴×10⁻⁷=1.6×10⁷=16×10⁶ m s⁻¹.

Why the other options are wrong

More Motion of a Charge in an Electric Field questionsAll Motion of a Charge in an Electric Field questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer