13. Solar photovoltaic cells a. are made of semiconductors b. are the only signi

Question

13. Solar photovoltaic cells a. are made of semiconductors b. are the only significant electricity producing technology without any moving parts. c. have high initial capital costs but very low maintenance costs. d. have zero fuel cost e. all of the above 14. To minimize transmission losses, electricity is transmitted from power plants at a. high voltages c. low resistances b. high currents d. low power 15. For photovoltaic cells, the potential difference for two silicon cells in series will be about a. 0.1 volts b. 0.5 volts c.1.0 volts d. 2.0 volts e.5.0 volts (12 pts) Multiple Choice: 6 questions, 2 pt each 16. According to the Stefan-Boltzmann Law, doubling an objects temperature will increase the power with which it radiates heat energy by a factor of d. 16. 17. How much current will be drawn by a 1200-watt hair dryer operating at 120 volts? a. 0.1 amps b. 1.0 amps C.1.44 amps d. 10 amps e. 20 amps 18. How much power does a 12-V car battery producing 30 A deliver to your car's electrical system. a. 360 w b. 0.4 W c. 12 W d. 2.5 W d. 30 W 19. If the current through a 7.5 ohm resistor is 4 amps, then the voltage drop through the resistor will be a. 15 volts. b. 10 volts. c. 30 volts. d. 60 volts. 20. A transformer increases voltage from 100 V in the primary coil to 10,000 V in the secondary coil. Which coil has more loops? a. the primary coil b. the secondary coil c. Both coils have the same number of loops. d. It depends on the current supplied to the primary coil. 21. A transformer increases voltage from 100 V in the primary coil to 10,000 V in the secondary coil. How does this change the current? a. current increases by a factor of 100 b. current increases by a factor of 10 c. current decreases by a factor of 10 d. current decreases by a factor of 100

Explanation / Answer

16.

According to stefan boltzmann's law, power is given by:

P = A*e*sigma*T^4

Which means power is directly porportional to T^4

P2/P1 = (T2/T1)^2

Given that T2 = 2*T1

P2 = P1*(2*T2/T1)^4

P2 = 16*P1

Correct option is D.

17.

Power = V*i

i = P/V = 1200/120 = 10 Amp

Correct option is D

18.

P = V*i

P = 12*30 = 360 W

Correct option is A

19.

Ohm's law is

V = i*R

V = 4*7.5 = 30 V

Correct option is C.

20.

for transformers

Vp/Vs = Np/Ns

Which means coil which have higher voltage will have higher number of loops

Correct option is B.

21.

Vp/Vs = is/ip = Np/Ns

is = ip*(Vp/Vs)

is = ip*(100/10000)

is = ip/100

So Current decreases by a factor of 100

Correct option is D.

Please Upvote.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.