A Solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting spherical shell. Let the potential difference between the surface of the solid sphere and the outer of the shell be V. If the shell is given a charge -3Q the new potential difference between the same two surfaces is 1. 2V 2. V/2 3. V 4. -2V

A square loop of side l , resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v , then the power needed is (a) BRlv (b) B²l²v²/R (c) B l²v²/ R (d) Blv/R

A steel wire of length l has a magnetic moment M .It is then bent into a semicircular arc. The new magnetic moment is a) M b) 2M/π c) M/l d) Ml

An AC voltage source of variable angular frequency ω and fixed amplitude V connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When ω is increased (a) The bulb glows dimmer (b) The bulb glows brighter (c) Net impedance of circuit is unchanged (d) Total impedance of the circuit increases

An air capacitor is charged with an amount of charge q and dipped into an oil tank. If the oil is pumped out, the electric field between the plates of capacitor will (a) increase (b) decrease (c) remain the same (d) becomes zero

An alternating e.m.f. of angular frequency ω is applied across an inductance. The instantaneous power developed across it has an angular frequency (a) ω/4 (b) ω/2 (c) ω (d) 2 ω

An electric charge of 425 f μC is removed from a fully charged capacitor of capacitance 8.5μF. Its potential will be lowered by: (a) 75 V (b) 100 V (c) 85 V (d) 50 V

Cathode rays travelling from west to east enter into region of electric field directed towards south to north in the plane of paper. The deflection of cathode rays is towards: (A) East (B) West (C) North (D) South

Electric flux emanating through a surface element placed in an electric field is (A) 10 units (B) 20 units (C) 4 units (D) 16 units

Electric potential at a distance r from the point charge is proportional to 1. \(r^2\) 2. r-1 3. r0 4. r+1

Equipotential surfaces at a great distance from a collection of charges whose total sum is not zero are approximately (a) spheres (b) planes (c) paraboloids (d) ellipsoids

For any charge configuration equipotential surface through a point is normal to the electric field. 1. Since W=Fscosθ is zero so field is normal to the surface 2. As W≠0 3. Work done can be Zero if Field is parallel to the field 4. None of these

Four charges 2C,-3C,-4C and 5C respectively are placed at the four corners of a square .Which of the following statements is true for the point of intersection of the diagonals. 1. E=0,V=0 2. E=0 V≠0 3. E≠0 V=0 4. E≠0 V≠0

Four point charges –Q,-q,2q,2Q are placed at different corners of a square . The relation between Q and q for which the potential at the center of the square is zero 1.Q=q 2.Q=1/q 3.Q=-q 4. Q=-1/q

Graph represents q verses V for two capacitors having same plate separation but different plate area . Which is the correct option