NEET Physics Electric Charges And Fields Class 12 Questions

Figure below show regular hexagons, with charges at the vertices. In which case, the electric field at the centre zero?

Match the Column I (electric lines of force) with Column II (types of charge) and select the correct answer from the codes given below.

The spatial distribution of the electric field due to charges (A, B) is shown in figure. Which one of the following statements is correct

Two charges of +25 × 10⁻⁹ coulomb and –25 × 10⁻⁹ coulomb are placed 6 m apart. Find the electric field intensity ratio at points 4 m from the centre of the electric dipole (i) on axial line (ii) on equatorial line

Two identical charged conducting spheres A and B have their centres separated by a certain distance. Charge on each sphere is q and the force of repulsion between them is F. A third identical uncharged conducting sphere is brought in contact with sphere A first and then with B and finally removed from both. New force of repulsion between spheres A and B (Radii of A and B are negligible compared to the distance of separation so that for calculating force between them they can be considered as point charges) is best given as :

An electric dipole with dipole moment 5 × 10⁻⁶ Cm is aligned with the direction of a uniform electric field of magnitude 4 × 10⁵ N/C. The dipole is then rotated through an angle of 60° with respect to the electric field. The change in the potential energy of the dipole is:

An electric dipole is placed at an angle of 30° with an electric field of intensity 2×10⁵ N C⁻¹. It experiences a torque equal to 4 N m. Calculate the magnitude of charge on the dipole, if the dipole length is 2 cm.

If ∮_S <span style="display:inline-block;position:relative;padding-top:0.4em;">E<span style="position:absolute;top:0;left:50%;transform:translateX(-50%);font-size:0.7em;">→</span></span>·<span style="display:inline-block;position:relative;padding-top:0.4em;">dS<span style="position:absolute;top:0;left:50%;transform:translateX(-50%);font-size:0.7em;">→</span></span> = 0 over a surface, then:

Two point charges −q and +q are placed at a distance of L, as shown in the figure. The magnitude of electric field intensity at a distance R (R >> L) varies as:

A dipole is placed in an electric field as shown. In which direction will it move?

Two charged spherical conductors of radius R₁ and R₂ are connected by a wire. Then the ratio of surface charge densities of the spheres (σ₁/σ₂) is :

A hollow metal sphere of radius R is uniformly charged. The electric field due to the sphere at a distance r from the centre:

Two parallel infinite line charges with linear charge densities +λ C/m and −λ C/m are placed at a distance of 2R in free space. What is the electric field mid-way between the two line charges?

Two point charges A and B, having charges + Q and – Q respectively, are placed at certain distance apart and force acting between them is F. If 25% charge of A is transferred to B, then force between the charges becomes:

An electron falls from rest through a vertical distance 'h' in a uniform and vertically upward directed electric field 'E'. The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance 'h'. The time of fall of the electron, in comparison to the time of fall of the proton is

The diagrams below show regions of equipotentials. A positive charge is moved from A to B in each diagram. Maximum work is required to move q in figure (c).

Suppose the charge of a proton and an electron differ slightly. One of them is –e, the other is (e + Δe). If the net of electrostatic force and gravitational force between two hydrogen atoms placed at a distance d (much greater than atomic size) apart is zero, then Δe is of the order of [Given mass of hydrogen mₕ = 1.67 × 10⁻²⁷ kg]

Two identical charged spheres suspended from a common point by two massless strings of lengths l, are initially at a distance d (d<< l) apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity v. Then v varies as a function of the distance x between the spheres, as

The electric field in a certain region is acting radially outward and is given by E = Ar. A charge contained in a sphere of radius ‘a’ centred at the origin of the field, will be given by

A conducting sphere of radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere respectively are

An electric dipole of dipole moment p is aligned parallel to a uniform electric field E. The energy required to rotate the dipole by 90° is:

A charge 'q' is placed at the centre of the line joining two equal charges 'Q'. The system of the three charges will be in equilibrium if 'q' is equal to: