Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Electrostatics question

2018 · Q158
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Physics
  4. /Electrostatics
  5. /2018 · Q158

Electrostatics question

2018 · Q158

NEETPhysicsElectrostaticsMCQ+4 / −1
An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E. The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h. The time of fall of the electron, in comparison to the time of fall of the proton is
  1. A
    smaller
  2. B
    5 times greater
  3. C
    10 times greater
  4. D
    equal
View written solutionFree

Correct answer: A

Force experienced by a charged particle in an electric field, F = qE

As F = ma

∴\therefore∴ ma = qE

⇒\Rightarrow⇒ a = qEm{{qE} \over m}mqE​

As electron and proton both fall from same height at rest. Then initial velocity = 0

From the formula, s = ut + 12at2{1 \over 2}a{t^2}21​at2

∴\therefore∴ h = 12at2{1 \over 2}a{t^2}21​at2

⇒\Rightarrow⇒ h = 12qEmt2{1 \over 2}{{qE} \over m}{t^2}21​mqE​t2

∴\therefore∴ t = 2hmqE\sqrt {{{2hm} \over {qE}}} qE2hm​​

⇒\Rightarrow⇒ t ∝\propto∝ m\sqrt m m​ as ‘q’ is same for electron and proton.

Since, electron has smaller mass so it will take smaller time.

PreviousNext

More from Electrostatics

  • Suppose the charge of a proton and an electron differ slightly. One of them is −e, the other is (e + Δe). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (musch greater…2017 · MCQ
  • The diagrams below show regions of equipotentials. A positive charge is moved from A to B in each diagram. Includes diagram2017 · MCQ
  • Two identical charged spheres suspended from a common point by two massless strings of lengths l, are initially at a distance d(d < < l) apart because of their mutual repulsion. The charges begin to leak from both the spheres at…2016 · MCQ
  • An electric dipole is placed at an angle of 30o with an electric field intensity 2 × 105 N C−1. It experiences a torque equal to 4 N m. The charge on the dipole, if the dipole length is 2 cm, is2016 · MCQ
  • If potential (in volts) in a region is expressed as V(x, y, z) = 6xy − y + 2yz, the electric field (in N/C) at point (1, 1, 0) is2015 · MCQ
  • The electric field in a certain region is acting radially outward and is given by E = Ar. A charge contained in a sphere of radius 'a' centred at the origin of the field, will be given by2015 · MCQ
  • A conducting sphere of radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere rrespectively are2014 · MCQ
  • In a region, the potential is represented by V(x, y, z) = 6x − 8xy − 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is2014 · MCQ