01․ Two identical circular coils, one closed and another is little split (not enclosed) are placed in an uniform magnetic field which decrease at a constant rate. If the plane to the coils are perpendicular to the field which of the following statements is true?
Whenever a coil open or closed, cuts magnetic line of force, an emf is induced in it.
02․ A long wire composed of a smooth round conductor runs above and parallel to the ground (assumed to be a large conducting plane). A high voltage exits between the conductor and the ground. The maximum electric stress occur at
Since the distance from ground to lower surface is less than from ground to upper surface. So electric stress is maximum at lower surface.
03․ A loop is rotating about x-axis in a magnetic field, B = BO cos(ω + φ) ay. The voltage in the loop is
Whenever a moving circuit is kept in a time varying magnetic field induced emf have two components: One for time variation of B and other for turn motion of circuit in B.
04․ A metal sphere with 1 m radius and a surface charge density of 10 coulombs/m2 is enclosed in a cube of 10 m side. The total outward electric displacement normal to the surface of the cube is
D = q × 4π r2.
05․ An electric dipole of moment P is placed in front of a ground sphere. The change induced on the surface of the sphere is (Assume radius of sphere = R and distance from dipole to centre of sphere = d)
Charge induced on a spherical surface = - QR/D Where, Q = inducing point charge; D = distance of the point charge from the centre of sphere. Total charge induce in present case, Now for a dipole D is very small i.e. D << d Hence Q = PR/d2 where, P = qD, the dipole moment.
06․ What is the value of total electric flux coming out of a closed surface?
According to gauss theorem, the total electric flux through any closed surface surrounding charges is equal to the amount to charges enclosed by the surface.
07․ Electric field strength of charge
Electric field strength or electric field intensity.
08․ The statement which is not correct from the following:
It is E = ρL/(2πε0.r).
09․ Two infinite parallel metal plates are charged with equal surface charge density of the same polarity. The electric field in the gap between the plates is
For an infinite sheet of charge having surface charge density ρs, the electric field on either side is ρ/2ε and away from it assuming charge to be the positive). Therefore, in the region between the plates, the two fields are anti parallel and equal.
10․ An insulated metal sphere of 20 cm diameter is charged by rubbing with charges 2 × 10-8 C. Potential developed will be
r = d/2.