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The current through a 0.1-H inductor is i(t)=10te-5tA. Find the
(a) Voltage across the inductor and
(b) The energy stored in it.
Date posted:
May 12, 2021
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Figure 6.2 shows a rectangular loop of wire immersed in a nonuniform and varying magnetic
field B that is perpendicular to and directed into the page. The field’s magnitude is given by
B=4t2x2 , with B in teslas, t in seconds, and x in metres. The loop width w = 2.0 m and length l
= 3.0 m. What are the magnitude and direction of the induced emf around the loop at t = 0.10 s?
Date posted:
May 12, 2021
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A coil consists of 200 turns of wire having a total resistance of 2.0 Ω. Each turn is a square of
side 18cm, and a uniform magnetic field directed perpendicular to the plane of the coil is turned
on. If the field changes linearly from 0 to 0.50 T in 0.80 s, what is the magnitude of the induced
emf in the coil while the field is changing?
Date posted:
May 12, 2021
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A long, straight wire carries a current of 5.00 A. At one instant, a proton, 4.00 mm from the wire,
travels at 1.50 x103 m/s parallel to the wire and in the same direction as the current (Fig.5.2).
(a) Find the magnitude and direction of the magnetic field created by the wire.
(b) Find the magnitude and direction of the magnetic force the wire’s magnetic field exerts on the proton.
Date posted:
May 12, 2021
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A long, straight wire of radius R carries a steady current I0 that is uniformly distributed through
the cross-section of the wire (Fig. 5.1). Using Ampere’s law, calculate the magnetic field a
distance r from the center of the wire in the regions r > R and r < R .
Date posted:
May 12, 2021
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State Ampere’s Law.
Date posted:
May 12, 2021
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A wire carries a current of 22.0 A from West to East. Assume that at this location the magnetic
field of Earth is horizontal and directed from south to north and that it has a magnitude of
0.500 x 10-4 T.
(a) Find the magnitude and direction of the magnetic force on a 36.0-m length of wire.
(b) Calculate the gravitational force on the same length of wire if it’s made of copper and has a
cross-sectional area of 2.50 x 10-6 m2.
Date posted:
May 12, 2021
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A proton moves at 8.00 x 106 m/s along the x-axis. It enters a region in which there is a magnetic
field of magnitude 2.50 T, directed at an angle of 60.0° with the x-axis and lying in the xy - plane
(Fig. 4.3). Find the initial magnitude and direction of the magnetic force on the proton.
Date posted:
May 12, 2021
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The Earth's magnetic field is about 50 μT northward. Find the velocity that an electron moving
westward would have so that the magnetic force balances gravity.
Date posted:
May 12, 2021
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A battery, a capacitor and a resistor are connected as shown in figure below. Obtain an expression
for the charge after the switch is closed.
When switch is closed at 1, capacitor charging and when at position 2, the capacitor is
discharging.
Date posted:
May 12, 2021
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A charge q1 = 2.00 μC is located at the origin, and a charge q2 = -6.00 μC is located at (0, 3.00)
m, as shown in figure a.
(a) Find the total electric potential due to these charges at the point P, whose coordinates are
(4.00, 0) m.
(b) Find the change in potential energy of a 3.00 μC charge as it moves from infinity to point P
of (Fig a) such that the situation is as in Fig b.
Date posted:
May 11, 2021
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Two large, parallel, conducting plates are 12 cm apart and have charges of equal magnitude and
opposite sign on their facing surfaces. An electrostatic force of 3.9 x 10-15 N acts on an electron
placed anywhere between the two plates (Neglecting fringing)
(a) Find the electric filed at the position of the electron
(b) What is the potential difference between the plates?
Date posted:
May 11, 2021
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A rod of length l has a uniform positive charge per unit length λ and a total charge Q. Calculate the electric field at a point P that is located along the long axis of the rod and a distance a from one end.
Date posted:
May 11, 2021
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A charge q1 = 7.0 μC is located at the origin, and a second charge q2 = -5.0μC is located on the x
axis, 0.30 m from the origin. Find the electric field at the point P, which has coordinates (0, 0.40) m.
Date posted:
May 11, 2021
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Two particles are fixed to an x- axis: particle 1 of charge -2.1 x 10-8 C at x = 20 cm and particle 2
of charge q2 = -4.00q1 at x = 70 cm. At what coordinate on the axis is the net electric field
produced by the particles equal to zero?
Date posted:
May 11, 2021
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What is the magnitude of a point charge whose electric field 50 cm away has a magnitude of 2.0 N/C?
Date posted:
May 11, 2021
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Three point charges lie along the x axis as shown in figure 2.2. The positive charge q1 =15.0μC is
at x = 2.00 m, the positive charge q2 = 6.00 μC is at the origin, and the resultant force acting on
q3 is zero. What is the x coordinate of q3?
Date posted:
May 11, 2021
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Consider three point charges located at the corners of a right triangle as shown in figure 2.1, where q1= q3 = 5.0 μC, q2 = -2.0 μC and a = 0.10 m. Find the resultant force exerted on q3.
Date posted:
May 11, 2021
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The electron and proton of a hydrogen atom are separated (on the average) by a distance of approximately 5.3 x 10-11 m. Find the magnitudes of the electric force between the two particles.
Date posted:
May 11, 2021
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How much charge is represented by 4,600 electrons?
Date posted:
May 11, 2021
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Find the currents l1, l2, and l3 in the circuit shown in figure below.
Date posted:
May 11, 2021
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Find the current I in the circuit of the figure below.
Date posted:
May 11, 2021
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The terminal p.d of a battery is 12 V when an external resistance of 20 Ω is connected and 13.5 V when an external resistance of 45 Ω is connected. Calculate the emf and internal resistance of the battery.
Date posted:
May 11, 2021
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A battery of emf 40 V and internal resistance 5 Ω is connected to a resistance of 15 Ω.
Calculate the terminal p.d.
Date posted:
May 11, 2021
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A cell of unknown emf E and internal resistance 2 Ω is connected to a 5 Ω resistance. If the terminal p.d V is 1.0 V, calculate E.
Date posted:
May 11, 2021
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Explain the difference between load resistance in a circuit and internal resistance in a battery.
Date posted:
May 11, 2021
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Four resistors are connected as shown in figure below.
(a) Find the equivalent resistance between points a and c.
(b) What is the current in each resistor if a potential difference of 42 V is maintained between a and c ?
Date posted:
May 11, 2021
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Consider five resistors connected as shown in figure below. Find the equivalent resistance between points a and b.
Date posted:
May 11, 2021
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Define current density and show how it is related to drift velocity.
Date posted:
May 11, 2021