Submit on Tuesday, March 6, 2018, at the end of lecture. Complete the follouwing

Question

Submit on Tuesday, March 6, 2018, at the end of lecture. Complete the follouwing problems in groups of three or four. You must turn but everyone must contribute. Make sure to put your name on each page you turn in. For full credit, show all of your in only one set of answers per group work and/or explain your reasoning. 1. A 1800 W toaster, 75 W lamp, and 1400 W electric frying pan are con- nected in parallel to a 120 V battery. The battery is connected in series to a circuit breaker which will blow when the current is larger than 20 A. Treating these devices as resistors, determine if the circuit breaker will blow or not 2. A Wheatstone bridge is a device that can be used to determine resistance. There is a variable resistor R, that can be configured such that the current through the galvanometer (a device that measures current, labeled with a G") is zero. This is depicted in Figure 1. The unknown resistor is R Show that the unknown resistor can be written as R the current th R2R./Ri when 3. In Figure 2, two capacitor combinations are shown, each connected to a resistor and a battery. When the switch is closed, the capacitors will charge. After a long period of time, the capacitors are fully charged. At this time, which set of capacitors stores more energy? 4. In Figure 3, three identical resistors R = 20, are shown. If the maximum power that this circuit can dissipate is 48.0 W, find the maximum current which can flow through each of the resistors. What is the maximum power that each can dissipate? 5. While buying a refrigerator, you notice that its specifications indicate that it draws 3.5 A of current if connected to a 120 V battery. If you are going to run the refrigerator 50% of the time and you are being charged S0.12 per kWh, how much will it cost to run this refrigerator per month? Assume 30 days per month. A kWh is a unit of energy equal using 1000 W for 1 hour. Recall that 1W = 1J/18, and treat the refrigerator as a large resistor

Explanation / Answer

According to cheggs policy, I will answer only the first question.

Since all of them are connected in parallel,

all of them will have a potential difference of 120V across them.

Now, Power = Current*Potential difference = I*V

for the toaster,

I*120 = 1800

or I=15 A

for the lamp,

I*V = 75

or I*120=75

or I=0.625 A

For the frying pan,

IV=power

or I*120=1400

or I=11.667

so total current = 11.667+0.625+15

=27.925

Hence the circuit breaker will blow since the current is greater than 20 A

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---