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Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. If the charge on each is 6.5 × 10–7 C? The radii of A and B are negligible compared to the distance of separation. Suppose the spheres A and B in

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Coulomb’s law for electrostatic force between two point charges and Newton’s law for gravitational force between two stationary point masses, both have inverse-square dependence on the distance between the charges and masses respectively. Estimate the accelerations of electron and proton due to the electrical force of their mutual attraction

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An AC voltage is applied to a resistance R and an inductor L in series. If R and the inductive reactance are both equal to `3Omega`, the phase difference (in rad) between the applied voltage and the current in the circuit is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The self-inductance of a coil is L. Keeping the length and area same, the number of turns in the coil is increased to four times. The self-inductance of the coil will be

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Induced CurrentThe steady current in the coil `C_2` as shown below produces a steady magnetic field. As coil `C_2` is moved towards the coil `C_1`, the galvanometer shows a deflection. This indicates that electric current is induced in coil `C_1`. When `C_2` is moved away, the galvanometer shows a deflection again, but this time in the opposite direction. This deflection is based upon the Faraday’s law of electromagnetic induction.What will be the direction of deflection of galvanometer, when `C_2` is moved

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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In Fig., two positive charges q2 and q3 fixed along the y axis, exert a net electric force in the + x direction on a charge q1 fixed along the x axis. If a positive charge Q is added at (x, 0), the force on

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Figure shows a convex spherical surface with centre of curvature C separating the two media of refractive indices `n_1 and n_2`. Draw a ray diagram showing the formation of the image of a point object O lying on the principal axis. Derive the relationship between the object and image distance in terms of refractive indices of the media and the radius of curvature R of the surface. (ii) Define the magnifying power of a compound microscope. Why should both the objective and the eyepiece have small focal lengths in a

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Consider a metal ring kept on top of a fixed solenoid (say on a carboard) (Fig ). The centre of the ring coincides with the axis of the solenoid. If the current is suddenly switched on, the metal ring jumps up.

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A metal road moves at a constant velocity in a direction perpendicular to its length & a constant uniform magnetic field too. Select the correct statement (s) from the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Charge on a body is `q_1` and it is used to charge another body by induction. Charge on second body is found to be `q_2` after charging,

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A rectangular conductor `SPQR` is placed in a uniform magnetic field perpendicular to the plane and extending from `x=0` to `x=b` as shown below. The arm `PQ` of length `l` is moving from `x=0` to `x=2b` with constant speed `v`. Find the flux and emf induced in the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) A conductor A with a cavity as shown in Fig. is given a charge Q. Show that the entire charge must appear on the outer surface of the conductor.(ii) Another conductor B with charge q is inserted into the cavity keeping B insulated from A. Show that the total charge on the outside surface of A is Q + q [Fig.(b)].(iii) A sensitive instrument is to be shielded from the strong electrostatic fields in its environment. Suggest a possible

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A cylindrical space of radius R is filled with a uniform magnetic induction B parallel to the axis of the cylinder. If `(dB)/(dt) =` constant, the graph, showing the variation of induced electric field with distance r from the axis of cylinder, isConsider a conducting circular loop placed in a magnetic field as shown in figure. When magnetic field changes with time, magnetic flux also changes and emf `e=-(dphi)/(dt)` is induced. If resistance of loop is R then induced current is `i=e/R`. For current, charges must have non–zero average velocity. Magnetic force cannot make the stationary charges to move. Actually

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Draw a ray diagram showing the formation of the image by a point object on the principal axis of a spherical convex surface separating two media of refractive indices `n_1 and n_2`, when a point source is kept in rarer medium of refractive index `n_1`. Derive the relation between object and image distance in terms of refractive index of the medium and radius of curvature of the surface. Hence, obtain the expression for lens maker's formula in the case of thin convex

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(1) The electric field `vecE` due to a point change at any point near to it is defined as: `vecE=Lim vecF/q`where q is the test charge and `vecF` is the force acting on it. What is the significance of lim `qtoo` in this expression?(2) Two charges each `2 xx 10^(-7)` C but opposite in sign forms a system. These charges are located at points A (0,0, -10) cm and B(0,0, +10) cm respectively. What is the total charge and electric dipole moment of the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Quantisation of charge implies : (a) charge cannot be destroyed (b) charge exists on particles (c) there is a minimum permissible charge on a particle (d) charge, which is a fraction of a charge on an electron is not possible

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Two charges ±10 µC are placed 5.0 mm apart. Determine the electric field at a point P on the axis of the dipole 15 cm away from its centre O on the side of the positive charge, as shown in Fig. ,

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An uniform electric field E exists along positive x-axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle 60° with x-axis is 10 J. Then the magnitude of electric field

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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At what depth in an ocean will a tube of air have one – fourth volume it will have on reaching the surface? Given Atmospheric Pressure = 76 cm of Hg and density of Hg =

asked Mar 19, 2022 in 11th Physics by varun (6.7k points)

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How can you charge a metal sphere positively without touching

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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