Three capacitors of capacitances 1 µF, 2µF and 4μF are connected first in a series combination and then in a parallel combination. The ratio their equivalent capacitances will be
2 : 49
49 : 2
4 : 49
49 : 4
A parallel plate capacitor with air as the dielectric has capacitance C. A slab of dielectric constant K and having the same thickness as the separation between the plates is introduced so as to fill one-fourth of the capacitor as shown in the figure. The new capacitance will be
A parallel palte condenser is filled with two dielectrics as shown in figure. Area of each pate is A m2 and the separation is d metre. The dielectric constants are K1 and K2 respectively. Its capacitance in farad will be
Two equal negative charges - q are fixed at the point (0, a) and (0, - a) on the y-axis. A positive charge Q is released from rest at the point (2a, 0) on the x-axis. The charge wil
execute SHM about the origin
move to the origin and remain at rest
move to infinity
execute oscillatory but not SHM
A charged particle is accelerated by a potential of 200 V. If its velocity is 8.4 × 108 m/s, then value of e/m for that particle is
17.6 × 1016
14.5 × 1012
1.76 × 1015
1.45 × 1015
Two capacitors of capacities C1 and C2 are charged upto the potential V1 and V2 then condition for not flowing the charge between on connected them in parallel is
C1 = C2
C1V1 = C2V2
V1 =V2
Electric field at point 20 cm away from the centre of dielectric sphere is 100 V/m, radius of sphere is 10 cm, then the value of electric field at a distance 3 cm from the centre is
100 V/m
125 V/m
120 V/m
0
D.
0
Inside a dielectric sphere, electric field is zero.
Dielectric, insulating material or a very poor conductor of electric current. When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material.
Magnetic field of the earth is H =0.3 g. A magnet is vibrating 5 oscillations per min then the dippreciation required in the magnetic field of the earth of increase time period upto 10 oscillations per minute is
2.25 g
0.6 g
0.9 g
0.12 g
Two small balls, each carrying a charge q are suspended by equal insulator strings of length l m from the hook of a stand. This arrangement is carried in a satellite in space. The tension in each string will be