A Gaussian sphere encloses an electric dipole within it. The total flux across the sphere is

• zero

• half that due to a single charge

• double that due to a single charge

• dependent on the position of the dipole

The specific charge of a proton is 9.6 x10⁷ C kg^-1  The specific charge of an alpha particle will be

• 9.6 x10⁷ C kg^-1

• 19.2 x10⁷ C kg^-1

• 4.8 x10⁷ C kg^-1

• 2.4 x10⁷ C kg^-1

Point charges + 4q, - q and+ 4q are kept on the x-axis at points x = 0, x = a and x = 2a respectively, then

• only- q is in stable equilibrium

• all the charges are in stable equilibrium

• all the charges are in unstable equilibrium

• none of the above

If E_a be the electric field strength of a short dipole at a point on its axial line and E_e that on equilateral line at the same distance, then

• E_e = 2E_a

• E_a = 2E_e

• E_a = E_e

• none of these

165.

Charges 4Q, q and Q are placed along x-axis at positions x = 0, x = l/2 and x = l, respectively. Find the value of q so that the force on charge Q is zero:

• Q

• $\frac{\mathrm{Q}}{2}$

• $-\frac{\mathrm{Q}}{2}$

• -Q

Two small charged spheres A and B have charges 10 C and 40 C respectively and are held at a separation of 90 cm from each other. At what distance from A, the electric intensity would be zero?

• 22.5 cm

• 18 cm

• 36 cm

• 30 cm

A charged particle moves in an electric field from A to B, then from B to A :

• If W_AB > W_BA, then the field is conservative

• If W_AB + W_BA = 0, then the field is conservative

• If W_AB + W_BA > 0, then the field is conservative

• If W_AB = W_BA, then the field is conservative

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line?

• 0°

• 90°

• 180°

• None of these

Two spheres of radii R₁ and R₂ respectively are charged and joined by a wire. The ratio of the electric field of spheres is :

• $\frac{{\mathrm{R}}_2^2}{{\mathrm{R}}_1^2}$

• $\frac{{\mathrm{R}}_1^2}{{\mathrm{R}}_2^2}$

• $\frac{{\mathrm{R}}_2}{{\mathrm{R}}_1}$

• $\frac{{\mathrm{R}}_1}{{\mathrm{R}}_2}$

The figure shows three points A, B and C in a region of a uniform electric field $\overrightarrow{\mathrm{E}}$. The line AB is perpendicular and BC is parallel to the field lines. Then which of the following holds good?

• V_A = V_B = V_C

• V_A = V_B > V_C

• V_A = V_B < V_C

• V_A > V_B = V_C