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In Exercise 4.11 obtain the frequency of revolution of the electron in its circular orbit. Does the answer depend on the speed of the electron?

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

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(i) A circular coil of 30 turns and radius 8.0 cm carrying a current of 6.0 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1.0 T. The field lines make an angle of 60° with the normal of the coil. Calculate the magnitude of the counter torque that must be applied to prevent the coil from turning with the normal of the coil. Calculate the magnitude of the counter torque that must be applied to prevent the coil from turning.(ii) Would your answer change, if the circular coil in (a) were replaced by a planar coil

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

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Two concentric circular coils X and Y of radii 16 cm and 10 cm, respectively, lie in the same vertical plane containing the north to south direction. Coil X has 20 turns and carries a current of 16 A; coil Y has 25 turns and carries a current of 18 A. The sense of the current in X is anticlockwise, and clockwise in Y, for an observer looking at the coils facing west. Give the magnitude and direction of the net magnetic field due to the coils at their

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

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A magnetic field of 100 G (1 G = 10–4 T) is required which is uniform in a region of linear dimension about 10 cm and area of cross-section about 10–3 m2 . The maximum current-carrying capacity of a given coil of wire is 15 A and the number of turns per unit length that can be wound round a core is at most 1000 turns m–1. Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not

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

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A toroid has a core (non-ferromagnetic) of inner radius 25 cm and outer radius 26 cm, around which 3500 turns of a wire are wound. If the current in the wire is 11 A, what is the magnetic field(i) outside the toroid,(ii) inside the core of the toroid, (iii) in the empty space surrounded by the

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

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An electron emitted by a heated cathode and accelerated through a potential difference of 2.0 kV, enters a region with uniform magnetic field of 0.15 T. Determine the trajectory of the electron if the field(i) is transverse to its initial velocity,(ii) makes an angle of 30º with the initial

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

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A magnetic field set up using Helmholtz coils (described in Exercise 4.16) is uniform in a small region and has a magnitude of 0.75 T. In the same region, a uniform electrostatic field is maintained in a direction normal to the common axis of the coils. A narrow beam of (single species) charged particles all accelerated through 15 kV enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undeflected when the electrostatic field is 9.0 × 10–5 V m–1, make a simple guess as to what the

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

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A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires.(i) What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero?(ii) What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before? (Ignore the mass of the wires.) g = 9.8 ms–2

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

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The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart? Is the force attractive or

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

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A uniform magnetic field of 1.5 T exists in a cylindrical region of radius10.0 cm, its direction parallel to the axis along east to west. A wire carrying current of 7.0 A in the north to south direction passes through this region. What is the magnitude and direction of the force on the wire if,(i) the wire intersects the axis,(ii) the wire is turned from N-S to northeast-northwest direction,(iii) the wire in the N-S direction is lowered from the axis by a distance of 6.0

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

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A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in Fig. What is the force on each case? Which case corresponds to stable

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

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A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.10 T normal to the plane of the coil. If the current in the coil is 5.0 A, what is the(i) total torque on the coil,(ii) total force on the coil,m2(iii) average force on each electron in the coil due to the magnetic field? (The coil is made of copper wire of cross-sectional area 10–5 , and the free electron density in copper is given to be about 1029

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

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A solenoid 60 cm long and of radius 4.0 cm has 3 layers of windings of 300 turns each. A 2.0 cm long wire of mass 2.5 g lies inside the solenoid (near its centre) normal to its axis; both the wire and the axis of the solenoid are in the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to an external battery which supplies a current of 6.0 A in the wire. What value of current (with appropriate sense of circulation) in the windings of the solenoid can support the weight

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

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A galvanometer coil has a resistance of 12 Ω and the metre shows full scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18

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

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A galvanometer coil has a resistance of 15 Ω and the metre shows full scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6

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

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A short bar magnet placed with its axis at 30° with an external field of 800 G experiences a torque of 0.016 Nm.(i) What is the magnetic moment of the magnet?(ii) What is the work done in moving it from its most stable to most unstable position?(iii) The bar magnet is replaced by a solenoid of cross-sectional area 2 × 10–4 m2 and 1000 turns, but of the same magnetic moment. Determine the current flowing through the

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

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A short bar magnet placed with its axis at 30° with an external field of 800 G experiences a torque of 0.016 Nm.What is the magnitude of the equatorial and axial fields due to a bar magnet of length 5.0 cm at a distance of 50 cm from its mid-point? The magnetic moment of the bar magnet is 0.40 A

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

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Fig. shows a small magnetised needle P placed at a point O. The arrow shows the direction of its magnetic moment. The other arrows show different positions (and orientations of the magnetic moment) of another identical magnetised needle Q. (i) In which configuration the system is not in equilibrium?(ii) In which configuration is the system in (i) stable, and (ii) unstable equilibrium?(iii) Which configuration corresponds to the lowest potential energy among all the configurations shown?

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

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A domain in ferromagnetic iron is in the form of a cube of side length 1µm. Estimate the number of iron atoms in the domain and the maximum possible dipole moment and magnetisation of the domain. The molecular mass of iron is 55 g/mole and its density is 7.9 g/cm3 . Assume that each iron atom has a dipole moment of 9.27×10–24 A

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

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A closely wound solenoid of 800 turns and area of cross section 2.5 × 10–4 m2 carries a current of 3.0 A. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic

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

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