l vodafone TR 4G 21:33 @ %40 a session.masteringphysics.com C e hw5 An ordinary

Question

l vodafone TR 4G 21:33 @ %40 a session.masteringphysics.com C e hw5 An ordinary flashlight uses two D-cell 1.5-V batteries connected in series as in the figures. The bulb draws 410 mA when turned on. PartA Calculate the resistance of the bulb. Express your answer to two significant figures and include the appropriate units R- Value Units Part B Calculate the power dissipated. Express your answer to two significant figures and include the appropriate units. P. Value Units Part C By what factor would the power increase if four D-cells in series were used with the same bulb? (Neglect heating effects of the filament.) Paturm to Assignment Provide Feedback

Explanation / Answer

a)

Total Voltage = 1.5V + 1.5V (series connection) = 3V.

Total Current = 410mA = 0.410A

Resistance = Volts / Current ....(Ohm's Law)

Resistance = 3V / 0.410A = 7.3 Ohms

b)

P = V2/R = 32/7.317 = 1.2 W

c)

Power = Volts-Squared / Resistance

So if you double the voltage by doubling the number of batteries, then the power goes up by the square of that... or 4 times.

You should not try this because the batteries will also heat up with more current being drawn from them. There is a risk that the batteries will leak or explode.

N.B.: Charge your phone.

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