Electrostatics - (1 and 2)
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Sathya SeelanElectrostatics - (1 and 2)
Uploaded by
Sathya SeelanElectrostatics
Read the assertion and reason carefully to mark the correct option out of the options given below:
(a) If both assertion and reason are true and the reason is the correct explanation of the
assertion.
(b) If both assertion and reason are true but reason is not the correct explanation of the
assertion.
(c) If assertion is true but reason is false.
(d) If the assertion and reason both are false.
(e) If assertion is false but reason is true.
1. Assertion : The coulomb force is the dominating force in the universe.
Reason : The coulomb force is weaker than the gravitational force.
2. Assertion : If three capacitors of capacitance C1 < C2 < C3 are connected in parallel then their
equivalent capacitance Cp > Cs
1 1 1 1
Reason : = + +
C p C1 C 2 C3
3. Assertion : A metallic shield in form of a hollow shell may be built to block an electric field.
Reason : In a hollow spherical shield, the electric field inside it is zero at every point.
4. Assertion : Electrons move away from a low potential to high potential region.
Reason : Because electrons has negative charge
5. Assertion : If the distance between parallel plates of a capacitor is halved and dielectric
constant is made three times, then the capacitor becomes 6 times.
Reason : Capacity of the capacitor does not depend upon the nature of the material.
6. Assertion : A parallel plate capacitor is connected across battery through a key. A dielectric
slab of constant K is introduced between the plates. The energy which is stored
becomes K times.
Reason : The surface density of charge on the plate remains constant or unchanged.
7. Assertion : Electric lines of force cross each other.
Reason : Electric field at a point superimpose to give one resultant electric field.
8. Assertion : If a proton and an electron are placed in the same uniform electric field. They
experience different acceleration.
Reason : Electric force on a test charge is independent of its mass.
9. Assertion : Dielectric breakdown occurs under the influence of an intense light beam.
Reason : Electromagnetic radiations exert pressure.
10. Assertion : When charges are shared between any two bodies, no charge is really lost, but
some loss of energy does occur.
Reason : Some energy disappears in the form of heat, sparking etc.
11. Assertion : Annihilation of electron and positron is an example of decay of charges.
Reason : In the process of annihilation an electron and a positron combine to give a gamma
particle.
12. Assertion : Surface of a symmetrical conductor can be treated as equipotential surface.
Reason : Charges can easily flow in a conductor.
13. Assertion : The capacity of a given conductor remains same even if charge is varied on it.
Reason : Capacitance depends upon nearly medium as well as size and shape of conductor.
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14. Assertion : A charged capacitor is disconnected from a battery. Now if its plates are
separated farther, the potential energy will fall.
Reason : Energy stored in a capacitor is equal to the work done in charging it.
15. Assertion : Charge is invariant.
Reason : Charge does not depend on speed of frame of reference.
16. Assertion : Mass of ion is slightly differed from its element.
Reason : Ion is formed, when some electrons are removed or added so mass changes.
17. Assertion : Charge is quantized
Reason : Charge, which is less than 1 C is not possible
18. Assertion : If a point charge q is placed in front of an infinite grounded conducting plane
surface, the point charge will experience a force.
Reason : This force is due to the induced charge on the conducting surface which is at
zero potential.
19. Assertion : The surface charge densities of two spherical conductors of different radii are
equal. Then the electric field intensities near their surface are also equal.
Reason : Surface charge density is equal to charge per unit area.
20. Assertion : Three equal charges are situated on a circle of radius r such that they form on
equilateral triangle, then the electric field intensity at the centre is zero.
Reason : The force on unit positive charge at the centre, due to the three equal charges
are represented by the three sides of a triangle taken in the same order.
Therefore, electric field intensity at centre is zero.
21. Assertion : On going away from a point charge or a small electric dipole, electric field
decreases at the same rate in both the cases.
Reason : Electric field is inversely proportional to square of distance from the charge or
an electric dipole.
22. Assertion : The whole charge of a conductor cannot be transferred to another isolated
conductor.
Reason : The total transfer of charge from one to another is not possible.
23. Assertion : Conductors having equal positive charge and volume, must also have same
potential.
Reason : Potential depends only on charge and volume of conductor.
24. Assertion : At a point in space, the electric field points towards north. In the region,
surrounding this point the rate of change of potential will be zero along the east
and west.
Reason : Electric field due to a charge is the space around the charge.
25. Assertion : A point charge is brought in an electric field. The field at a nearby point will
increase, whatever be the nature of the charge.
Reason : The electric field is independent of the nature of charge.
26. Assertion : The force with which one plate of a parallel plate capacitor is attracted towards
the other plate is equal to square of surface density per per unit area.
Reason : The electric field due to one charged plate of the capacitor at the location of the
other is equal to surface density per .
27. Assertion : The lightening conductor at the top of high building has sharp pointed ends.
Reason : The surface density of charge at sharp points is very high resulting in setting up of
electric wind.
28. Assertion : Circuit containing capacitors should be handled cautiously even when there is no
current.
Reason : The capacitors are very delicate and so quickly break down.
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29. Assertion : The tyres of aircrafts are slightly conducting.
Reason : If a conductor is connected to ground, the extra charge induced on conductor
will flow to ground.
30. Assertion : A bird perches on a high-power line and nothing happens to the bird.
Reason : The level of bird is very high from the ground.
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