True/False Physics Question?

Household wiring has a 120 V source for nearly all circuits, including your light bulbs. Imagine that you have two separate circuits with two different light bulbs plugged into the wall socket -- a 60 W bulb and a 120 W bulb. Which of the following statements are true about the comparison between these two circuits?





a) 120 W bulb will be brighter


b) the current flowing through the two bulbs is equal


c) it will cost more money to run the 120 W bulb for an hour


d) the voltage across the 120 W bulb is greater


e) the resistance of the 60 W bulb is equal to the 120 W bulb

True/False Physics Question?
Assuming that both bulbs are in parallel





a) 120 W bulb will be brighter (Yes)


b) the current flowing through the two bulbs is equal (NO) the current trough the 60 W bulb will be less


P=IV or I=P/V


I(60)= 60/120= 0.5A


I(120)= 120/120= 1A


c) it will cost more money to run the 120 W bulb for an hour (Yes as apposed to 60W it will be twice as much)


d) the voltage across the 120 W bulb is greater (No it is the same)


e) the resistance of the 60 W bulb is equal to the 120 W bulb


(No it is not.)





P=V^2/R and in both cases V is the same


Resistace is R= V^2/P so


R(60W)=120^2/60=240 ohm


R(120w)= 120^2/(120) =120 ohm