A charge Q is placed at the corner of a cube. The electric flux through all the six faces of the cube is

(a)

\(\frac { Q }{ { 3\varepsilon }_{ 0 } } \)

(b)

\(\frac { Q }{ { 6\varepsilon }_{ 0 } } \)

(c)

\(\frac { Q }{ { 8\varepsilon }_{ 0 } } \)

(d)

\(\frac { Q }{ { \varepsilon }_{ 0 } } \)

Which graph shows the variation of electric field E due to a hollow spherical conductor of radius R as a function of distance from the centre of the sphere?

(a)

(b)

(c)

(d)

In a hollow spherical shell potential (V) changes with respect to distance (r) from centre.
\(\left[ { V }_{ inside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }R } r\le R,\quad { V }_{ outside }=\frac { Q }{ 4\pi { \varepsilon }_{ 0 }r } r\ge R,V\alpha \frac { 1 }{ r } \right] \)

(a)

(b)

(c)

(d)

What physical quantities may X and Y represent? [Y represents the first mentioned quantity].

(a)

K.E - velocity of a particle

(b)

pressure - temperature of a given gas (constant volume)

(c)

capacitance - charge to give a constant potential

(d)

potential - capacitance to give a constant charge

During charging a capacitor variation of potential V of the capacitor with time t as shown a

(a)

(b)

(c)

(d)

Charge Q on a capacitor varies with voltage V as shown in graph, where Q is along X-axis and V along Y-axis. The area of triangle OAB represents

(a)

capacitance

(b)

capacitive reactance

(c)

magnetic field between the plates

(d)

energy stored in the capacitor

A condenser of 2μF capacitance is charged steadily from 0 to 5 coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condensor [Q = C V ]

(a)

(b)

(c)

(d)

In two concentric hollow spheres of radii r and R (>r), the charge Q is distributed such that their surface densities are some. Then the potential at their common centre is

(a)

\(\frac { Q({ R }^{ 2 }+{ r }^{ 2 }) }{ 4\pi { \varepsilon }_{ 0 }(R+r) } \)

(b)

\(\frac { QR }{ R+r } \)

(c)

zero

(d)

\(\frac { Q({ R }+{ r }) }{ 4\pi { \varepsilon }_{ 0 }({ R }^{ 2 }+{ r }^{ 2 }) } \)

A point charge q is placed at a distance a/2 directly above the centre of a square of side 'a'. The electric flux through the square is

(a)

\(\frac { q }{ { \varepsilon }_{ 0 } } \)

(b)

\(\frac { q }{ { \pi \varepsilon }_{ 0 } } \)

(c)

\(\frac { q }{ {4 \pi \varepsilon }_{ 0 } } \)

(d)

\(\frac { q }{ {6 \pi \varepsilon }_{ 0 } } \)

A polythene piece rubbed with wool is found to have negative charge of 3.2 x 10^-7C. Estimate the number of electrons transferred from wool to polythene

(a)

2 x 10¹²

(b)

3 x 10¹²

(c)

4 x 10¹²

(d)

5 x 10¹²

A Gaussian surface in the figure is shown by dotted line. The electric field on the surface will be

(a)

due to q₁ and q₂ only

(b)

due to q₂ only

(c)

zero

(d)

due to all

A charge q is placed at the centre of a cubical box of side with top open. The flux of electric field through the surface of the cubical box is

(a)

Zero

(b)

\(\frac { q }{ { \varepsilon }_{ 0 } } \)

(c)

\(\frac { q }{ 6{ \varepsilon }_{ 0 } } \)

(d)

\(\\ \frac { 5q }{ 6{ \varepsilon }_{ 0 } } \)

Electric field intensity at a point due to an infinite sheet of charge having surface charge density σ is E. If the sheet were conducting, electric intensity would be

(a)

\(\frac{E}{2}\)

(b)

E

(c)

2E

(d)

4E

Surface density of charge on a sphere of radius R in terms of electric intensity E at a distance r in free space is

(a)

\({ \varepsilon }_{ 0 }E{ \left( \frac { R }{ r } \right) }^{ 2 }\)

(b)

\(\frac { { \varepsilon }_{ 0 }ER }{ { r }^{ 2 } } \)

(c)

\({ \varepsilon }_{ 0 }E{ \left( \frac { r }{ R } \right) }^{ 2 }\)

(d)

\({ e }_{ 0 }E\frac { r }{ { R }^{ 2 } } \)

The electric flux over a sphere of radius 1m is ф. If radius of the sphere were doubled without changing the charge enclosed, electric flux would become

(a)

2ф

(b)

\(\\ \\ \\ \frac { \phi }{ 2 } \)

(c)

\(\\ \\ \\ \frac { \phi }{ 4 } \)

(d)

ф

Electric field at a distance r from infinitely long conducting sheet is proportional to 

(a)

r¹

(b)

r²

(c)

r^3/2

(d)

independent of r

A charge q is enclosed as shown in fig. The electric flux is 

(a)

maximum in (i)

(b)

maximum in (ii)

(c)

maximum in (iii)

(d)

equal in all

A charge q₁ exerts force on charge q₂. If another charge q₃ is brought near, the force of q₁, exerted on q₂, will be

(a)

decreased

(b)

increased

(c)

remains unchanged

(d)

increased if q₃ is of same sign as q₁ and decreased if q₂ is of opposite sign.

Find the electric field at x = 5m from the graph.

(a)

2 V/m

(b)

-2.5 V/m

(c)

2/5 V/m

(d)

-2/5 V/m

Van de Graaff generator produces an electrostatic potential difference of_______ volts.

(a)

10⁸

(b)

10⁹

(c)

10⁷

(d)

10¹⁰