The charges on two spheres are +7mC and –5mC respectively. They experience a force F. If each of them is given an additional charge of –2mC, the new force of attraction will be
(A) F
Three charges each equal to 2 μC are placed at the corners of an equilateral triangle. If force between any two charges is 2F, then the net force on either will be:
A charge q is placed at one corner of the cube. The electric flux passing through any one of its face is
Two charges q and –3q are placed on x-axis separated by distance d. Where a third charge 2q should be placed such that it will not experience any force ?
Two charges of 2uC and 5uC are placed 2.5 cm apart. The ratio of Coulomb's force experienced by them is
The given figure shows tracks of three charged particles in a uniform electrostatic field. Which of them is probably an α-particle?
(A) 1
(B) 2
(C) 3
(D) None of the above
A point charge +Q is placed in the vicinity of a conducting surface. Draw the electric field lines between the surface and the charge.
Find the expression for electric field intensity in an axial position due to electric dipole.
Which field is more effective in electromagnetic waves?
(A) Electric field
(B) magnetic field
(C) both electric and magnetic field
(D) none of these
The capacitance of a capacitor will decrease if we introduce a slab of:
(a) copper
(b) aluminium
(c) zinc
(d) None of these
The locus of all particles in a medium, vibrating in the same phase is called
(a) wavelet.
(b) fringe.
(c) wave front.
(d) None of these.
The electric potential of earth is taken to be zero, because earth is a good
(a) insulator
(b) conductor
(c) semiconductor
(d) dielectric
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
The current sensitivity of a Galvanometer can be increased by decreasing-
a) Magnetic field B
b) No. of turns N
c) Torsional constant k
d) Area of the coil A
In Young’s double slit experiment, using sodium light (λ = 5898) , 92 fringes are seen. If given colour (λ= 5461) is used, how many fringes will be seen?
I. 67
II. 95
III. 99
IV. 84