Roro312
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1. If the potential difference across the nerve of a frog is 85mV and its resistance is 2.5x10^2 Ω what current will flow through the nerve? Answer: 3.4x10^ -4
2.If all other factors remained the same, what change in resistance would result if the radius of a wire were doubled? Answer: 1.7 x 10
3. Human hands have a resistance of about 1.0x 10^ 5 Ω when dry and .5x10^3 Ω when wet. When a current of about 1.2mA passes through the body of a person will feel a tingle. The person will lose muscular control (become paralyzed) at a current of about 20mA .suppose the person touches a 120 V wire. Describe the difference in what happens with dry hands and with wet hands. CAUTION: Do not try this. Answer: 1.2 mA
4. What is the equivalent (total) resistance when resistors have values of 10 Ω 25 Ω and 30 Ω are connected in series? Answer: 65 Ω
5. Six identical lights are connected in series to a 100 v supply. If the total current flowing is 750 mA ,calculate:
a) the potential across each bulb Answer: 16.7 v
b) the resistance of each bulb Answer: 22 Ω
c) the equivalent resistance of the string of lights Answer: 799.98 Ω
6. What is the total resistance of a parallel connection of two resistors if one has a resistance of 60 Ω and the other has a resistance of 20 Ω? Answer: 15 Ω
7. Six identical light bulbs are connected together in parallel. Each bulb has a resistance of 25 Ω. The lights are to be connected to 10v supply.
a. What is the total resistance of the lights? Answer: 4.2 Ω
b. What is the total current leaving the power supply? Answer: 2.38 Ω
c. What is the current through each bulb? Answer: 0.4 A
8. A parallel combination of three identical resistors has a total resistance of 12 Ω What is the resistance of each resistor? Answer: 4 Ω
9. Two resistors are connected in parallel. The total resistance of the combination is known to be 6.0 Ω. If one of the resistors is 10 Ω what is the value of the other?
Answer: 15 Ω
10. An 800w hair dyer was plugged into a 120 v wall socket. What current will it draw? Answer: 6.7 A
11. A toy truck uses a 1.5 v cell. If the toy operates at a power of 120 mw, what is its resistance? Answer: 18.75 Ω
12. A small electric motor has a resistance of 4.5 Ω. If the motor operates using 670 mA of current, what is its power? Answer: 18.75 Ω
13. What is the total cost of lighting a 60W bulb for 10 minutes? Answer: 51 cent
14. A coin-operates clothes dryer is rated at 5.0kW and runs for 12 minutes when $1 is inserted. How much is left for the owner after energy costs? Answer: $1
15. A typical bill for electricity is $70 a month. How much energy in kWh is used?
Answer: 0.1kwh
16. A typical nuclear electric power plant has a power of 1.0 GW (10 w). If all the energy produced in a day’s operation were sold, how much money would the plant earn?
Answer: $ 2.4x10^7
Thanks for your help...if you can help me correct anything wrong that would be great
2.If all other factors remained the same, what change in resistance would result if the radius of a wire were doubled? Answer: 1.7 x 10
3. Human hands have a resistance of about 1.0x 10^ 5 Ω when dry and .5x10^3 Ω when wet. When a current of about 1.2mA passes through the body of a person will feel a tingle. The person will lose muscular control (become paralyzed) at a current of about 20mA .suppose the person touches a 120 V wire. Describe the difference in what happens with dry hands and with wet hands. CAUTION: Do not try this. Answer: 1.2 mA
4. What is the equivalent (total) resistance when resistors have values of 10 Ω 25 Ω and 30 Ω are connected in series? Answer: 65 Ω
5. Six identical lights are connected in series to a 100 v supply. If the total current flowing is 750 mA ,calculate:
a) the potential across each bulb Answer: 16.7 v
b) the resistance of each bulb Answer: 22 Ω
c) the equivalent resistance of the string of lights Answer: 799.98 Ω
6. What is the total resistance of a parallel connection of two resistors if one has a resistance of 60 Ω and the other has a resistance of 20 Ω? Answer: 15 Ω
7. Six identical light bulbs are connected together in parallel. Each bulb has a resistance of 25 Ω. The lights are to be connected to 10v supply.
a. What is the total resistance of the lights? Answer: 4.2 Ω
b. What is the total current leaving the power supply? Answer: 2.38 Ω
c. What is the current through each bulb? Answer: 0.4 A
8. A parallel combination of three identical resistors has a total resistance of 12 Ω What is the resistance of each resistor? Answer: 4 Ω
9. Two resistors are connected in parallel. The total resistance of the combination is known to be 6.0 Ω. If one of the resistors is 10 Ω what is the value of the other?
Answer: 15 Ω
10. An 800w hair dyer was plugged into a 120 v wall socket. What current will it draw? Answer: 6.7 A
11. A toy truck uses a 1.5 v cell. If the toy operates at a power of 120 mw, what is its resistance? Answer: 18.75 Ω
12. A small electric motor has a resistance of 4.5 Ω. If the motor operates using 670 mA of current, what is its power? Answer: 18.75 Ω
13. What is the total cost of lighting a 60W bulb for 10 minutes? Answer: 51 cent
14. A coin-operates clothes dryer is rated at 5.0kW and runs for 12 minutes when $1 is inserted. How much is left for the owner after energy costs? Answer: $1
15. A typical bill for electricity is $70 a month. How much energy in kWh is used?
Answer: 0.1kwh
16. A typical nuclear electric power plant has a power of 1.0 GW (10 w). If all the energy produced in a day’s operation were sold, how much money would the plant earn?
Answer: $ 2.4x10^7
Thanks for your help...if you can help me correct anything wrong that would be great
