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Consider a sphere of radius R with charge density distributed as `ρ (r ) = kr ' for ' r le R` `ρ (r ) =0 ' for ' r > R` . (i) Find the electric field at all points r.(ii) Suppose the total charge on the sphere is 2e where e is the electron charge. Where can two protons be embedded such that the force on each of them is zero. Assume that the introduction of the proton does not alter the negative charge

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

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Two fixed, identical conducting plates (α & β ) , each of surface area S are charged to –Q and q, respectively, whereQ > q > 0. A third identical plate (γ ), free to move is located on the other side of the plate with charge q at a distance d (Fig ). The third plate is released and collides with the plate β . Assume the collision is elastic and the time of collision is sufficient to redistribute charge amongst β & γ . (i) Find the electric field acting on the plate γ before collision.(ii)

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

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There is another useful system of units, besides the SI/mks A system, called the cgs (centimeter-gram-second) system. In this system Coloumb’s law is given by`F=(Qq)/r^2 hatr` where the distance r is measured in cm (= 10–2 m), F in dynes (=10–5 N) and the charges in electrostatic units (es units), where 1es unit of charge =`1/[3] ×10^(-9)`The number [3] actually arises from the speed of light in vaccum which is now taken to be exactly given by c = 2.99792458 × 108 m/s. An approximate value of c then is c = [3] × 108 m/s. (i)

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

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Two charges –q each are fixed separated by distance 2d. A third charge q of mass m placed at the mid-point is displaced slightly by x (x << d) perpendicular to the line joining the two fixed charged as shown in Fig. . Show that q will perform simple harmonic oscillation of time period..

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

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Total charge –Q is uniformly spread along length of a ring of radius R. A small test charge +q of mass m is kept at the centre of the ring and is given a gentle push along the axis of the ring. (i) Show that the particle executes a simple harmonic oscillation.(ii) Obtain its time

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

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A positive charge Q is uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring as shown in then

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

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A square of side L meters lies in the x-y plane in a region, where the magnetic field is given by `B =B_o (2hati + 3hatj + 4hatk)` where Bo is constant. The magnitude of flux passing through the square

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

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A loop, made of straight edges has six corners at A(0,0,0), B(L,O,0) C(L,L,0), D(0,L,0) E(0,L,L) and F(0,0,L). A magnetic field ` B=B_o( hati +hat k)T` is present in the region. The flux passing through the loop ABCDEFA (in that order)

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

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A cylindrical bar magnet is rotated about its axis (Fig ). A wire is connected from the axis and is made to touch the cylindrical surface through a contact.

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

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There are two coils A and B as shown in Fig A current starts flowing in B as shown, when A is moved towards B and stops when A stops moving. The current in A is counterclockwise. B is kept stationary when A moves. We can infer

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

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Same as problem 4 except the coil A is made to rotate about a vertical axis (Fig ). No current flows in B if A is at rest. The current in coil A, when the current in B (at t = 0) is counterclockwise and the coil A is as shown at this instant, t = 0,

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

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The self inductance L of a solenoid of length l and area of crosssection A, with a fixed number of turns N increases

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

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A metal plate is getting heated. It can be

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

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An e.m.f is produced in a coil, which is not connected to an external voltage source. This can be due

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

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The mutual inductance M12 of coil 1 with respect to coil

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

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A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. This can be

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

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Consider a magnet surrounded by a wire with an on/off switch S (Fig ). If the switch is thrown from the off position (open circuit) to the on position (closed circuit), will a current flow in the circuit? Explain. Bar magnet N Circuit closed Bar magnet N Circuit open Fig.

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

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A wire in the form of a tightly wound solenoid is connected to a DC source, and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil, will the current increase or decrease?

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

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A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease?

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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