NEET Electrostatic Practice Test
Questions No:1The centres of two identical small conducting spheres are 1 m apart. They carry charges of opposite kind and attract each other with a force F. When they are connected by a conducting thin wire they repel each other with a force \( \frac{F}{3} \) . What is the ratio of magnitude of charges carried by the spheres initially?
[A] 1 : 1
[B] 2 : 1
[C] 3 : 1
[D] 4 : 1
Questions No:2
A metallic sphere having no net charge is placed near a finite metal plate carrying a positive charge. The electric force on the sphere will be
[A] towards the plate
[B] away from the plate
[C] parallel to the plate
[D] zero
Questions No:3
The insulation property of air breaks down at E = 3 x 106 v/m . The maximum charge that can be given to a sphere of diameter 5 m is approximately (in coulombs)
[A] 2X\( 10^{-2} \)
[B] 2X\(10{^-3} \)
[C] 2X\( 10^{-4}\)
[D] 2X\( 10^{-5} \)
Questions No:4
The distance between the two charges 25µ C and 36 µ C is 11 cm At what point on the line joining the two, the intensity will be zero?
[A] At a distance of 5 cm from 25µ C
[B] At a distance of 5 cm from 36µ C
[C] At a distance of 4 cm from 25 µ C
[D] At a distance of 4 cm from 36µ C
Questions No:5
The electric field near a conducting surface having a uniform surface charge density σ is given by
[A] \( \frac{σ}{ ε_0}\) and is parallel to the surface
[B] \( \frac{2σ}{ ε_0}\) and is parallel to the surface
[C] \( \frac{σ}{ ε_0}\) and is normal to the surface
[D] \( \frac{2σ}{ ε_0}\) and is normal to the surface
Questions No:6
The unit of electric field is not equivalent to
[A] N/C
[B] J/C
[C] V/m
[D] J/C-M
Questions No:7
The unit of intensity of electric field is
[A] Newton/coulomb
[B] Joule/coulomb
[C] Volt-metre
[D] Newton/metre
Questions No:8
Two spheres of radius a and b respectively are charged and joined by a wire. The ratio of electric field of the spheres is
[A] \( \frac{a}{b} \)
[B] \( \frac{b}{a} \)
[C] \( \frac {a^2}{b^2} \)
[D] \(\frac{b^2}{a}\)
Questions No:9
A cube of side b has a charge q at each of its vertices. The electric field due to this charge distribution at the centre of this cube will be \( \frac{1}{4πε _0} \) times
[A] \( \frac{q}{b^2} \)
[B] \( \frac{q}{2b^2} \)
[C] \( \frac{32q}{b^2} \)
[D] zero
Questions No:10
Electric field intensity at a point in between two parallel sheets with like charges of same surface charge densities (σ)
[A] \( \frac{σ}{ 2 ε_0} \)
[B] \( \frac{σ}{ε_0} \)
[C] Zero
[D] \( \frac{2σ}{ε_0} \)
Questions No:11
Two point charges (+Q) and (— 2Q) are fixed on the X-axis at positions aand 2 a from origin respectively. At what positions on the axis, the resultant electric field is zero?
[A] Only x = \( \sqrt{2}a \)
[B] Only x =\( \sqrt{2}a \)
[C] Both x = ± \( \sqrt{2}a \)
[D] Only x = \( \frac{3a}{2} \)
Questions No:12
Two point charges q and 2q are placed some distance apart. If the electric field at the location of q be E, then that at the location of 2 q will be
[A] 3E
[B] \( \frac{E}{2} \)
[C] E
[D] None of these
Questions No:13
Infinite charges of magnitude q each are lying at x = 1, 2, 4, 8, … metre on X-axis. The value of intensity of electric field at point X = 0 due to these charges will be
[A] 12 x\(10^9\) q N/C
[B] zero
[C] 6x\(10^9\) q N/C
[D] 4x\(10^9\) q N/C
Questions No:14
Angle between equipotential surface and lines of force is
[A] zero
[B] \(180^0\)
[C] \(90^0\)
[D] \( 45^0\)
Questions No:15
If a charged spherical conductor of radius 10 cm has potential V at a point distant 5 cm from its centre, then the potential at a point distant 1 5 cm from the centre will be
[A] \( \frac{1}{3} \) V
[B] \( \frac{2}{3} \) V
[C] \( \frac{3}{2} \) V
[D] 3 V
Questions No:16
Two unilike charges of magnitude q are separated by a distance 2d. The potential at a point midway between them is
[A] zero
[B] \( \frac{1}{4πε _0} \)
[C] \( \frac{1}{4πε_0} \) \( \frac{q}{d} \)
[D] \( \frac{1}{4πε_0} \)\( \frac{2q}{d} \)
Questions No:17
Two spheres A and B of radius a and b respectively are at same electric potential. The ratio of the surface charge densities of A and B is
[A] \( \frac{a}{b} \)
[B] \( \frac{b}{a} \)
[C] \( \frac{ a^2}{ b^2} \)
[D] \( \frac{ b^2}{ a^2} \)
Questions No:18
Point charge q1 = 2 µ C and q2 = – 1 µ C are kept at points x = 0 and x = 6 respectively. Electrical potential will be zero at points
[A] x = 2 and x = 9
[B] x = 1 and x = 5
[C] x = 4 and x = 1 2
[D] x = – 2 and x = 2
Questions No:19
Eight small drops, each of radius rand having same charge q are combined to form a big drop. The ratio between the potentials of the bigger drop and the smaller drop is
[A] 8 : 1
[B] 4 : 1
[C] 2 : 1
[D] 1 : 8
Questions No:20
Eight oil drops of same size are charged to a potential of 50 V each. These oil drops are merged into one single large drop. What will be the potential of the large drop?
[A] 50V
[B] 100V
[C] 200V
[D] 400V
Questions No:21
Electric potential at a point X from the centre inside a conducting sphere of radius R and carrying charge Q is
[A] \( \frac{1}{4πε _0} \) \( \frac{Q}{R} \)
[B] \( \frac{1}{4πε _0} \) \( \frac{Q}{X} \)
[C] \( \frac{1}{4πε_0}\) \( \frac{X}{Q} \)
[D] Zero