For a CE transistor amplifier, the audio signal voltage across the collector resistance of 2 k⦠is 2V. Given, the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is 1 kâ¦.
Given Vce = 2V, Rc = 2k⦠, β = 100, R1 = 1kâ¦,
We need to find
iB and VB
ic = Collector current = Vce / Rc = 2V / 2k⦠= 2V / 2 x10-3⦠= 1 x 10-3 A = 1.0mA
iB = base current = ic / β = 1.0m A / 100 = 0.01m A
iB RB = Input signal voltage = (0.01 mA) (1kâ¦) = (0.01 x 10-3A) (1 x 103â¦) = 0.01V = 10mV
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(a) Estimate the number of electrons transferred (from which to which?)
(b) Is there a transfer of mass from wool to polythene?
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A conducting sphere of radius 10 cm has an unknown charge. If the electric field 20 cm from the centre of the sphere is 1.5 × 103 N/C and points radially inward, what is the net charge on the sphere?
A point charge of 2.0 μC is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?
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(a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane?
(b) What is the flux through the same square if the normal to its plane makes a 60° angle with the x-axis?
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( b) 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. 1.36(b)].
(c) A sensitive instrument is to be shielded from the strong electrostatic fields in its environment. Suggest a possible way.
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(b) What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?
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(b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 x 10-2T is set up at an angle of 30º with the axis of the solenoid?
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(b) The angle of dip at a location in southern India is about 18º.
Would you expect a greater or smaller dip angle in Britain?
(c) If you made a map of magnetic field lines at Melbourne in Australia, would the lines seem to go into the ground or come out of the ground?
(d) In which direction would a compass free to move in the vertical plane point to, if located right on the geomagnetic north or south pole?
(e) The earth's field, it is claimed, roughly approximates the field due to a dipole of magnetic moment 8 x 1022 J T-1 located at its centre. Check the order of magnitude of this number in some way.
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