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Electric Circuits
At which of the following values of t is the magnitude of the emf induced in the coil a maximum if a magnetic field perpendicular to the plane of a flat coil of copper wire has a time variation of the magnetic flux density given by B=Bosin(2tT) where Bo is the peak value of the magnetic flux density and T the period
A = T/8
B = T/4
C = 3T/8
D = T/2
A = T/8
B = T/4
C = 3T/8
D = T/2
Electric Circuits
A certain generator consists of a rectangular coil of 250 turns and an area of 50cm2. The coil rotates at a speed of 100 revolutions per second in a horizontal magnetic field 0.3T. Calculate the maximum induced emf in the coil and the induced emf when the plane of the coil is inclined at an angle of 35o to the horizontal
A = 235.6V and 193.0V
B = 344.2V and 230.2V
C = 144.3V and 96.5V
D = 56.4V and 26.7V
A = 235.6V and 193.0V
B = 344.2V and 230.2V
C = 144.3V and 96.5V
D = 56.4V and 26.7V
Electric Circuits
A 1000-turns coil of cross-sectional area 30cm2 rotates at a frequency of 120 Hz in a magnetic field 0.1 T. Calculate the peak value of the induced emf
A = 346.4V
B = 112.3V
C = 97.6V
D = 226.2V
A = 346.4V
B = 112.3V
C = 97.6V
D = 226.2V
Electric Circuits
A coil of inductance 2.0H and resistance 5 is connected to a 30V battery. Calculate the rate of current growth in the coil when the circuit has just been made and when the current reaches one-half of its steady-state vaule.
Electric Circuits
A potentiometer wire of length 100cm has a resistance of 10. It is connected in series to to a resistance R and a cell of emf 2V and negligible internal resistance. A source of emf of 10mV is balanced by a length of 40cm of the potentiometer wire. What is the value of the resistance R?
200
950
2000
790
200
950
2000
790
Electric Circuits
If the current in the 4.0- ohm resistor is 1.4 A, what is the magnitude of the potential difference, VA - VB?
Electric Circuits
A 0.96H coil carries a current of 8.0A. Calculate the energy stored in it
30.7J
45.3J
62.6J
27.3J
30.7J
45.3J
62.6J
27.3J
Electric Circuits
A rectangular wire loop of width 4.0cm is being pulled out of a magnetic field at a constant speed of 2.0m/s. The magnetic field is 0.30T and is uniform in the region, perpendicular and into the plane of the loop. What is the induced emf in the loop?
0.056V
0.012V
0.024V
0.087V
0.056V
0.012V
0.024V
0.087V
Electric Circuits
A rod of 5.0m length is held horizontally and with its axis in an east-west direction. It is allowed to fall straight down. What is the emf induced in it when its speed is 3.0m/s if the earth's magnetic field is 06010−4T with a dip angle of 53 degrees?
5410−4V
3610−3
2010−5
4210−4
5410−4V
3610−3
2010−5
4210−4
Electric Circuits
A certain inductor has an indutance of 0.50H and a resistance of 2.0. It is placed in series with a swtich, a 12.0-V battery and a 4.0 ohms resistor. Find the time constant of the circuit and the energy stored in the inductor.
0.83s and 100J
0.032s and 20J
0.47s and 5J
0.083s and 1J
0.83s and 100J
0.032s and 20J
0.47s and 5J
0.083s and 1J
