12 A certain lightbulb has a tungsten filament with a resistance of2.30 at 20.0°

Question

12 A certain lightbulb has a tungsten filament with a resistance of2.30 at 20.0°C and 8.20 when its temperature increases to Tr. Assume that the resistivity of tungsten varies linearly with temperature e over the large temperature range involved here. aw 4.5x10"(C" for tungsten. The temperature Trof the hot filament is closest to: a. 590°C b.. 1682°C c. 760°C d. 300 1240°C 13 What is the electric power delivered to the 3.000 resistor in the circuit shown the in igure? 0.8 W 48.0 w c. 22.0 W 42.0 V d. 1.9 W e. 7.2 W 14 The algebraic sum of all the potential differences around any closed circuit loop is to a Maximum because charges tend to move in the direction of maximum potential difference. completely used up after a c loop due b Zero because the current must be charge will tend Positive because charge to at a node. battery. accumulate the c because conservation. negative of d because the charges up at the terminal Negative ed. At a time the isclosed s initially 25% of its maximum possible value. 15 The energy stored in the cap has delivered the resistor this capacitor in the figure acitor to the 12 V, what is the power 0.40 and E

Explanation / Answer

12.

8.2 = 2.3[1 + (4.5X10-3/oC)(Tf - 20)]

Tf  = 590oC

So, correct option is a.

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13.

equivalent resistance of the circuit is,

Req = 4 + [(2X3)/5] + 1 = 6.2

So current by the battery is,

I = V/Req = 42V/6.2 = 6.77 A

This current is divided into the 2 and 3 resistors. So current through the 3 resistor is,

I3 = 2I/(2 + 3) = 2I/5 = 2(6.77A)/5

or, I3 = 2.7A

So power delivered to 3 resistor is,

P = I32(3) = (2.7A)2(3)

or, P = 22 W

So, correct option is c.

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14.

Across any loop sum of potential difference is zero due to conservation of energy.

So, correct option is d.

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15.

Figure not provided for the question....

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This concludes the answers. Check the answer and let me know if it's correct. If you need any more clarification, modification or correction, feel free to ask.....

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