All 6 questions! please show laid out workings open-Book/Noty Cloted Neiylhr! J

Question

All 6 questions! please show laid out workings

open-Book/Noty Cloted Neiylhr! J In Fig.6, when the switch is first closed, current flows through the resis tor from: a to b when b) b to a c) both directions d) current doesn't flow through the resistor In Fig.6, when the switch is opened after being closed for a while, current flows through the resistor from: a) a to b b) b toa c) both directions d) current doesn't flow through the resistor. 3) In Fig.6, when coil #2 is moved to the right away from co il fl with the switch closed, a tob b) b to a c) both directions d) current doesn't flow through the resistor. current flows through the resistor from: a to ai in 1o #1 #2 3 6 A calculator uses a 9v battery charger that gets its power from a standard 120v wal outlet. How many turns does the primary coil have compared to the secondary in the transformer? a) 13.3 times more b) 13.3 times less c) 9 times more d) 9 times less e) .075 times more They always have the same number of turns. 5) Find the impedance of the circuit showm in Fig. 14 a) 15.20 b) 33.1n c) 37.60 d) 43.4 120v e) 68.9 60Hz 10n 25 uf 15n 70 Fig. 14 What size (wattage) resistor is needed in Fig. 15? 200 ti fo tar's a) 1/8 W b) 1/4 W c) 1/2 W l 20 v TC10 Fig.15

Explanation / Answer

1) when the switch 1 is closed , the current in coil 1 is increased and the magnetic field due to induced current in 2 will be in oposite direction to that of 1 ,

hence , the direction of induced current is

a.) a to b

2)

as the when the switch 1 is opended , the current in coil 1 is decreasing and the magnetic field due to induced current in 2 will be in same direction to that of 1.

b)b to a

3)

When coil # 2 is moved to the right away from coil # 1 with the switch closed, the magnetic flux in coil 1 is decreasing and the magnetic field due to induced current in 2 will be in same direction to that of 1.

b.) b to a

4)

Np/Ns = Vp/Vs
Np/Ns = 120/9
Np/Ns = 13.3
Answer: a ) 13.3 times more

5)

Capacitors are parellel so Ceq = 25+55 = 80uf

impedence(Z) = sqrt(R^2+(XL-XC)^2)

Here XL = w*L

            = 2 *3.14*60*10*10^-3

            = 3.768

XC = 1/wC

     = 1/(2*3.14*60*80)

     = 33.174

R = 10+7+15

    = 32

Z = sqrt(R^2+(XL-XC)^2)

    = 43.4

Answer d) : 43.4

6)

120/200= V/50

hence V = 30 Volts

R = 16.1 (Color Code)

Z = 265

Answer a) 1/8 W

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