At a particular point, electric field depends upon

1

(a)

Source charge Q only

(b)

test charge q_o only

(c)

both Q and q₀

(d)

neither Q nor q_o

The SI unit of electric field intensity is 

1

(a)

N

(b)

N/C

(c)

C/m²

(d)

N/m²

Electric field due to an electric dipole is

1

(a)

spherically symmetric

(b)

cylindrically symmetric

(c)

asymmetric

(d)

none of the above

Electrostatic potential V at a point, distant r from a charge q varies as

1

(a)

q/r²

(b)

q²/r

(c)

q/r

(d)

q²/r²

Work done in carrying an electron from A to B lying on an equipotential surface of one volt potential is

1

(a)

1 eV

(b)

10 eV

(c)

1 volt

(d)

Zero

A closed surface in vacuum encloses charges -q and +3q. Another charge -2q lies outside the surface. Total electric flux over the surface is 

1

(a)

Zero

(b)

\(2 q\over \epsilon_o\)

(c)

\(-{3q\over \epsilon_o}\)

(d)

\(4q\over\epsilon_o\)

The number of electric lines of force radiating from a closed surface in vacuum is \(1.13\times 10^{11}\). The charge enclosed by the surface is

1

(a)

1 C

(b)

\(1\mu C\)

(c)

0.1 C

(d)

0.1\(\mu C\)

The electric field at a point is

1

(a)

always continuous

(b)

continuous if there is no charge at that point

(c)

discontinuous only if there is a negative charge at that point

(d)

discontinuous if there is a charge at that point

If there were only one type of charge in the universe, then

1

(a)

\(\oint _{ s }^{ }{ \overrightarrow { E } .\overrightarrow { ds } } \neq 0\) on any surface

(b)

\(\oint _{ s }^{ }{ \overrightarrow { E } .\overrightarrow { ds } } = 0\) if the charge is outside the surface

(c)

\(\oint _{ s }^{ }{ \overrightarrow { E } .\overrightarrow { ds } } \) could not be defined

(d)

\(\oint _{ s }^{ }{ \overrightarrow { E } .\overrightarrow { ds } } ={q\over \epsilon_o}\) if charges of magnitude q were inside the surface

Consider a region inside which there are various types of charges but the total charge is zero. At points outside the region

1

(a)

the electric field is necessarily zero

(b)

the electric field is due to the dipole moment of the charge distribution only

(c)

the dominant electric field is  \(\alpha {1\over r^3}\) , for large r , where r is the distance from a origin in this region.

(d)

the work done to move a charged particle along a closed path, away from the region, will be zero.

What is the cause of charging?

1

(a)

The cause of charging is actual transfer of electrons from one body to the other.

An isolated conducting sphere is given a positive charge. Does its mass increase, decrease or remain the same?

1

(a)

Its mass decreases slightly as it losses some electrons.

An ebonite rod is rubbed with fur or wool. What type of charges do they acquire?

1

(a)

The ebonite rod acquires a negative charge and fur/ wool acquires an equal positive charge.

What is meant by quantization of charge?

1

(a)

Charge on any body or particle can be integral multiple of charge on an electron  (-e), i.e.,
\(q=\pm ne,\) where n = 1,2,3,....

What do you mean by additivity of electric charge?

1

(a)

Additivity of charge means the total charge on a system is the algebraic sum (with proper signs) of all individual charges in the system.

What do you mean by conservation of electric charge?

1

(a)

Conservation of electric charge means that the total charge on an isolated system remains unchanged with time.

Is the total charge of the universe conserved?

1

(a)

Yes, charge conservation is a global phenomenon.

Why does an ebonite rod get negatively charged on rubbing with fur?

1

(a)

This is because electron in fur are less tightly bound than electrons in ebonite rod.

A glass rod rubbed with silk acquires a charge  +1.6 x 10^-12 C. What is the charge on the silk?

1

(a)

Charge on silk is equal and opposite to charge on glass rod. i.e., \(q=-1.6\times 10^{-12}C\)

Name any two basic properties of electric charge.

1

(a)

(i) Quantization of charge
(ii) Conservation of charge

Device an arrangemnet of three point charges separated by finite distances that has zero electric potential energy.

1

(a)

U = kq²/a - kq²/2a - kq²/2a = 0

Each of the uncharged capacitor in the fig.Has a capacitance of 25\(\mu \)F. what charge shall flow through the meter M when the switch S is Closed?

1

(a)

C = C+C+C = 3C = 75\(\mu \)F
Therefore m charge  = 75\(\mu \)F x 4200V = 315 mC.

Charge of 2C is placed at the centre of a cube volume 8 cm³. What is the electric flux passiing through one face?

1

(a)

Toral \(\phi \) = q0/\({ \varepsilon }_{ 0 }=2/{ \varepsilon }_{ 0 }\), \(\rightarrow\) flux through one face  = \(\phi \)/6 = 1/3 \({ \varepsilon }_{ 0 }\)

Three charges Q, +9 and +9 are placed at the vertices of a right angle isosceles triangle as shown, Find the magnitude of Q for which net electrostatic  energy of the configuration is zero. 

1

(a)

U = K (q²/a + qQ/a +qQ/2a)
But U = 0
Therefore ,Q -2q/(2 + \(\sqrt { 2 } \))