# How to Visualize Electric Fields

## Trending Questions

**Q.**

Write the properties of electric lines of force.

**Q.**

Two point charges 2 μC and 8μC are placed 12 cm apart. The position of point from 2 μC charge, where the electric field intensity is zero is:

12 cm

4 cm

2 cm

8 cm

**Q.**

Electric lines of force never intersect each other because

Lines of force always repel each other

Lines of force always attract each other

Point of intersection signifies two direction of electric field

From the point of intersection four tangent can be drawn which signifies four direction of field

**Q.**A ring of radius R having a linear charge density λ moves towards a solid imaginary sphere of radius R2, so that the centre of the ring passes through the centre of sphere. The axis of the ring is perpendicular to the line joining the centres of the ring and the sphere. The maximum flux through the sphere in this process is

- λRε0
- λR2ε0
- λπR4ε0
- λπR3ε0

**Q.**A charge of 1 C is located at the centre of a sphere of radius 10 cm whose centre coincides with that of a cube of side 20 cm. The ratio of the outgoing flux from the sphere to the outgoing flux from the cube will be

- more than one
- less than one
- one
- nothing can be said

**Q.**Three equal charges +q each, are placed at the three vertices of an equilateral triangle centred at the origin. They are held in equilibrium by a restoring force of magnitude F(r)=kr2 (where k is a constant, r is position of charge from origin) directed towards the origin. The distance of the any charge from the origin is (√3q2pπϵ0k)14 where p=

**Q.**

A
point charge causes an electric flux of −1.0 × 10^{3}
Nm^{2}/C
to pass through a spherical Gaussian surface of 10.0 cm radius
centered on the charge. (a) If the radius of the Gaussian surface
were doubled, how much flux would pass through the surface? (b) What
is the value of the point charge?

**Q.**A thin metallic spherical shell contains a charge Q on its surface. A point charge q1 is placed at the centre of the shell and another charge q2 is placed outside the shell. All the three charges are positive. Then, the force on charge q1 is

- Towards right
- Towards left
- Zero
- None of these

**Q.**

ABC is an equilateral triangle. Charges +q are placed at each corner. The electric intensity at O will be

**Q.**Calculate the electric field intensity E which would be just sufficient to balance the weight of an electron.If this electric field is produced by a second electron located below the first one what would be thedistance between them? \lbrack Given : e-1.6 x 1019 C, m, -9.1x 10-31 kg and g-9.8 m/s4

**Q.**

Write four properties of lines of force.

**Q.**A beam of electron passes, un-deflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons moves

- in a circular orbit
- along a parabolic path
- along a straight line
- in an elliptical orbit.

**Q.**(i) Use Gauss's law to find the electric field due to a uniformly charged infinite plane sheet. What is the direction of field for positive and negative charge densities ?

(ii) Find the ratio of the potential differences that must be applied across the parallel and series combination of two capacitors C1 and C2 with their capacitances in the ratio 1: 2 so that the energy stored in the two cases becomes the same.

**Q.**The electric field inside a spherical shell of uniform surface charge density is

- Zero
- Constant, less than zero
- Directly proportional to the distance from the centre
- None of the above

**Q.**Electric lines of force about negative point charge are:

- Circular, anticlockwise
- Circular, clockwise
- Radial, inward
- Radial, outward

**Q.**Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in

**Q.**

Can a body have a charge a) 0.32X10^-18C

b)0.64X10^-20C

c)4.8X10^-21C

Please explain in detail with a solution

**Q.**Apply Gauss law to show that for a charged spherical shell the electric field outside the shell is as if the entire charge were concentrated at the centr

**Q.**The wrong statement about electric lines of force is

- They do not intersect each other at a point
- They have the same form for a point charge and a sphere
- They have physical existence
- These originate from positive charge and end on negative charge

**Q.**Find out the magnitude of electric field intensity at point (2, 0, 0) due to a dipole of dipole moment →P=^i+√3^j kept at origin. Also find the potential at that point.

- |E|=K8, V=K2
- |E|=K2√2, V=7K8
- |E|=√7K8, V=K4
- |E|=K2, V=K4

**Q.**Assertion : Electric lines of force cross each other.

Reason : Electric field at a point superimpose to give one resultant electric field.

- If the assertion and reason both are false.
- If assertion is false but reason is true.
- If both assertion and reason are true but reason is not the correct explanation of the assertion.
- If assertion is true but reason is false.
- If both assertion and reason are true and the reason is the correct explanation of the assertion.

**Q.**

Why do electric lines of force never intersect each other?

**Q.**A charge q1 exerts some force on a second charge q2. If third charge q3 is brought near, the force of q1 exerted on q2

- Decreases
- Increases
- Remains unchanged
- Increases if q3 is of the same sign as q1 and decreases if q3 is of opposite sign

**Q.**Electric potential in a region is varying according to the relation V=3x22−y24 , where x and y are in meter and V is in volt. Electric field intensity in N/C at a point (1 m, 2 m) is

- 3^i−^j
- −3^i+^j
- 6^i−2^j
- −6^i+2^j

**Q.**

A spherical volume contains a uniformly distributed charge of volume density 2.0×10−4 Cm−3. Find the strength of electric field at a point inside the volume at a distance 4.0 cm from the centre.

3×104 NC

3×105 NC

3×106 NC

3×107 NC

**Q.**The centres of two identical small conducting spheres are 1m 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 F/3. What is the ratio of magnitude of charges carried by the spheres initially?

**Q.**N drops of mercury of equal radii and possessing equal charges combine to form a big spherical drop. If each individual drop has capacitance C , then the capacitance of the bigger drop compared to each individual drop is

- N times
- N23 times
- N13 times
- N53 times

**Q.**An electric line of force in the xy plane is given by equation x2+y2=1. A particle with unit positive charge, initially at rest at the point x = 1, y = 0 in the xy plane

- Will move along the circular line of force
- Information is insufficient to draw any conclusion
- Not move at all
- Will move along straight line

**Q.**

A charged oil drop is suspended in a uniform field of $3\times {10}^{4}V/m$ so that it neither falls nor rises. The charge on the drop will be,

(Take $massofcharge=9.9\times {10}^{-15}kg$ and $g=10m/{s}^{2}$)

$3.3\times {10}^{-18}C$

$3.2\times {10}^{-18}C$

$1.6\times {10}^{-18}C$

$4.8\times {10}^{-18}C$

**Q.**A mass m=20 g has a charge q=3.0 mC. It moves with a velocity of 20 m/s and enters a region of electric field of 80 N/C in the same direction as the velocity of the mass. The velocity of the mass after 3 sec in this region is–

- 80 m/s
- 56 m/s
- 44 m/s
- 40 m/s