A to Z Exams

The plates of a parallel plate capacitor are charged upto 200 volts. A dielectric slab of thickness 4 mm is inserted between its plates. Then, to maintain the same potential difference between the plates of the capacitor, the distance between the plates is increased by 3.2 mm. The dielectric constant of the dielectric slab is :

Two small angled prisms A and B deviate the blue rays by 70 and 90 and the red rays by 50 and 70 respectively. The prism which has a greater dispersive power is

The energy stored in a capacitor is given by (V = voltage, C = capacitance. q= charge)

Two charges 8C and -6C are placed at a distance of separation d between them and exerts a force of magnitude  F on each other. If a charge 8C is added to each of these and they are brought nearer to by a distance d/3, the magnitude of force between them

The force acting on a charge of 10-10C placed in an electric field of intensity 600 V/m is

Two unit negative charges are placed on a straight line. A positive charge q is placed exactly at the mid point between these unit charges. If the system of these three charges is in equilibrium, the value of q (inC) is

Work done by 0.1 mole of gas at 270C when it expands to double its volume at constant pressure is : (assume R = 2 cal/mol-1 K-1)

An infinitely long thin straight wire has uniform linear charge density of 1/3 coul.m-1.Then the magnitude of the electric intensity at a point 18 cm away is

A parallel plate capacitor has a capacitance of 10 micro farads without dielectric. A dielectric of dielectric constant 2 is used to fill exactly half the thickness between the plates. The capacitance in micro farads,now is

Under the application of force, a steel wire (Y = 19 x 1010Nm-2) of 5 m in length suffers an elongation of 1 mm. The potential energy stored per unit volume in this process, in joules per m3 is :

A charge of 4 μC is placed in a uniform electric field of intensity 100N/C. The force acting on the charge is

A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F. The decrease in the energy of the system will be

A 4 μF capacitor is charged by a 200V battery. It is then dis-connected from the supply and is connected to another uncharged 2 μF capacitor. During the process, loss of energy (in J) is

A thin prism of 40 angle gives a deviation of 2.40. The value of refractive index of the material of the prism is

Two electric charges 12 μC and -6 μC are placed 20 cm apart in air, there will be a point P at which electric potential is zero outside excluding the region between them. The distance of P from -6 μC charge is:

A pyknometer weight 40 g when empty and 1040 g when filled with mercury at 00C On heating to 1000C, 10 g of mercury overflows. If the coefficient of real expansion of mercury is 0.00020C the coefficient of expansion of glass is :

If the angle of a prism is 600 and angle of minimum deviation is 400, then the angle of refraction in the prism will be

A oil drop having a mass 4.8 x10-10 g and charge 2.4 x 10-18 C stands still between two charged horizontal plates separated by a distance of 1 cm. If now the polarity of the plates is changed, instantaneous acceleration of the drop is : (g = 10 ms-2)

A long string with a charge of λ per unit length passes through an imaginary cube of edge a. The maximum flux of the electric field through the cube will be

In a parallel plate air capacitor,of capacitance 4 F if the lower half of air space is filled with a material of dielectric constant 3, its capacitance changes to :

Three charges –q, +q and –q are placed at the corners of an equilateral triangle of side a. The resultant electric force on a charge +q placed at the centroid O of the triangle is

A parallel plate capacitor has a capacity 80x10-6 when air is present between the plates.The volume between the plates is then completely filled with a dielectric slab of dielectric constant 20. The capacitor is now connected to a battery of 30 V by wires. The dielelctric slab is then removed. Then, the charge that passes now through the wire is

When a dielectric material is introduced between the plates of a charged condenser the  electric field between the plates:

The phase difference between two vibrating particles separated by a distance of 11 metres into medium through which a progressive wave is travelling is 13200.If the frequency of the disturbance is 105 Hz, the phase velocity of the progressive wave in ms-l

A charged particle of mass 3 x 10-6 held stationary in spacing in an electric field of strength 106 NC-1 directed vertically downwards. The charge on the particle is :

Two charges of 50 μC and 100 μC are separated by a distance of 0.6m. The intensity of electric field at a point midway between them is

Three point charges 1C, -2C and -2C are placed at the vertices of an equilateral triangle triangle of side 1 metre The work done by an external force to increase the separation of the charges to 2 metre in joule is : (ε0= permittivity of air)

Two point charges -q and +q are located at points (0, 0, -a) and (0, 0, a) respectively. The electric potential at a point (0, 0, z), where z > a

Two positive charges q1=4x10-6C and q2=9x10-6C are placed 10cm apart in air. The position of a third charge to be placed between them, such that there will be no resultant force on it is

An infinite number of charges each of magnitude q are placed on x-axis at distances of 1, 2, 4, 8, ….. meter from the origin. The intensity of the electric field at origin is