Question 1

If a 500-W heater carries a current of 2.00 A,what is the voltage across the ends of the heating element?

Accepted Answer

A)  2000 V 
B)  125 V 
C)  0.008 V 
D)  250 V 
A)  2000 V 
B)  125 V 
C)  0.008 V 
D)  250 V

Question 2

An electric clothes dryer draws 20 A at 220 V.If the clothes put into the dryer have a mass of 7.0 kg when wet and 3.0 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,Lv = 2.26 × 106 J/kg. )

Accepted Answer

A)  55 min 
B)  26 min 
C)  16 min 
D)  34 min 
A)  55 min 
B)  26 min 
C)  16 min 
D)  34 min

Question 3

A water pump draws about 4.4 A when connected to 240 V.What is the cost (with electrical energy at 9 cents per kWh)of running the pump for 10 h?

Accepted Answer

A)  82 cents 
B)  8.0 cents 
C)  95 cents 
D)  15 cents 
A)  82 cents 
B)  8.0 cents 
C)  95 cents 
D)  15 cents

Question 4

An electric car is designed to run off a bank of 12-V batteries with total energy storage of 6.0 × 107 J.If the electric motor draws 6000 W in moving the car at a steady speed of 10 m/s,how far will the car go before it is "out of juice?"

Accepted Answer

A)  150 km 
B)  50 km 
C)  100 km 
D)  25 km 
A)  150 km 
B)  50 km 
C)  100 km 
D)  25 km

Question 5

In circuits involving resistors and capacitors the quantity 63% often arises.Which of the following is equivalent to this quantity?

Accepted Answer

A)  e​-2 
B)  1 - e​-1 
C)  1 - e​-2 
D)  e​-1 
A)  e​-2 
B)  1 - e​-1 
C)  1 - e​-2 
D)  e​-1

Question 6

A high voltage transmission line of diameter 2 cm and length 2 km carries a steady current of 1000 A.If the conductor is copper with a free charge density of 8 × 1028 electrons/m3,how long does it take one electron to travel the full length of the cable? (e = 1.6 × 10−19 C)

Accepted Answer

A)  8 × 102 s 
B)  8 × 108 s 
C)  8 × 106 s 
D)  8 × 104 s 
A)  8 × 102 s 
B)  8 × 108 s 
C)  8 × 106 s 
D)  8 × 104 s

Question 7

Five resistors each have resistance R.Three of the resistors are connected in series and this combination is then connected in parallel with the two other resistors which have been connected in series with each other.What is the equivalent resistance for this arrangement?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
A) 
  
B) 
  
C) 
  
D)

Question 8

A tungsten wire is used to determine the melting point of indium.The resistance of the tungsten wire is 6.000 Ω at 20°C and increases to 9.700 Ω as the indium starts to melt.αtungsten = 4.50 × 10−3 (°C)−1.What is the melting temperature of indium?

Accepted Answer

A)  351°C 
B)  731°C 
C)  132°C 
D)  157°C 
A)  351°C 
B)  731°C 
C)  132°C 
D)  157°C

Question 9

A metal wire has a resistance of 10.00 Ω at a temperature of 20.0°C.If the same wire has a resistance of 10.55 Ω at 90°C,what is the resistance when its temperature is 0.0°C?

Accepted Answer

A)  13.8 Ω 
B)  9.69 Ω 
C)  9.84 Ω 
D)  0.70 Ω 
A)  13.8 Ω 
B)  9.69 Ω 
C)  9.84 Ω 
D)  0.70 Ω

Question 10

A 100-W light bulb is in a socket supplied with 120 V.What is the current in the bulb?

Accepted Answer

A)  7200 A 
B)  0.83 A 
C)  1.4 A 
D)  0.50 A 
A)  7200 A 
B)  0.83 A 
C)  1.4 A 
D)  0.50 A

Question 11

Two resistors of values 6.0 and 12.0 Ω are connected in parallel.This combination in turn is hooked in series with an 8.0-Ω resistor and a 24-V battery.What is the current in the 12-Ω resistor?

Accepted Answer

A)  1.3 A 
B)  4.0 A 
C)  12 A 
D)  0.67 A 
A)  1.3 A 
B)  4.0 A 
C)  12 A 
D)  0.67 A

Question 12

Three wires of the same diameter and length are made from three different metals: copper (ρ​ = 1.7 × 10-8 Ω·m),aluminum (ρ​ = 2.7 × 10-8 Ω·m),and silver (ρ​ = 1.6 × 10-8 Ω·m).Which wire has the least resistance?

Accepted Answer

A)  the aluminum wire 
B)  the silver wire 
C)  the copper wire 
D)  Since insufficient information is given to find the resistance of each wire,one cannot find the answer. 
A)  the aluminum wire 
B)  the silver wire 
C)  the copper wire 
D)  Since insufficient information is given to find the resistance of each wire,one cannot find the answer.

Question 13

A metal wire has a resistance of 25.00 Ω under room temperature conditions of 25°C.When the wire is heated to 85°C the resistance increases by 1.95 Ω.What is the temperature coefficient of resistivity of this metal?

Accepted Answer

A)  1.3 × 10−3 (°
C) −1 
B)  1.5 × 10−3 (°
C) −1 
C)  5.0 × 10−4 (°
C) −1 
D)  2.5 × 10−3 (°
C) −1 
A)  1.3 × 10−3 (°
C) −1 
B)  1.5 × 10−3 (°
C) −1 
C)  5.0 × 10−4 (°
C) −1 
D)  2.5 × 10−3 (°
C) −1

Question 14

A lightbulb drawing a current of 0.60 A is run for 2.0 hours.How many electrons pass through the bulb during this process?

Accepted Answer

A)  2.7 × 1022 
B)  1.4 × 1019 
C)  5.4 × 1025 
D)  4.3 × 103 
A)  2.7 × 1022 
B)  1.4 × 1019 
C)  5.4 × 1025 
D)  4.3 × 103

Question 15

How long is a wire made from 200 cm3 of copper if its resistance is 8.5 ohms? The resistivity of copper is 1.7 × 10-5 Ω·m.

Accepted Answer

A)  10 m 
B)  2.2 × 102 m 
C)  7.1 m 
D)  3.0 × 103 m 
A)  10 m 
B)  2.2 × 102 m 
C)  7.1 m 
D)  3.0 × 103 m

Question 16

What is the current through the 6-Ω resistor?

Accepted Answer

A)  1.0 A 
B)  1.5A 
C)  0.50 A 
D)  2.0 A 
A)  1.0 A 
B)  1.5A 
C)  0.50 A 
D)  2.0 A

Question 17

Three 3.0-Ω resistors are connected in parallel to a 12.0-V battery.What is the current in any one of the resistors?

Accepted Answer

A)  0.75 A 
B)  12 A 
C)  4.0 A 
D)  1.3 A 
A)  0.75 A 
B)  12 A 
C)  4.0 A 
D)  1.3 A

Question 18

A 100-W bulb and a 40-W bulb,each designed for an applied voltage of 120 V,are connected in series across a 120-V source.What are the voltages across the 100-W bulb and across the 40-W bulb?

Accepted Answer

A)  86 V,34 V 
B)  30 V,90 V 
C)  90 V,30 V 
D)  34 V,86 V 
A)  86 V,34 V 
B)  30 V,90 V 
C)  90 V,30 V 
D)  34 V,86 V

Question 19

A hair dryer draws 1500 W,a curling iron draws 800 W,and an electric light fixture draws 500 W.If all three of these appliances are operating in parallel on a 120 V circuit,what is the total current drawn?

Accepted Answer

A)  23.3 A 
B)  20.8 A 
C)  36.7 A 
D)  19.4 A 
A)  23.3 A 
B)  20.8 A 
C)  36.7 A 
D)  19.4 A

Question 20

If a light bulb has half the resistance of a 50-W lightbulb,what would be its wattage? Assume both bulbs are attached to the same 120-V circuit.

Accepted Answer

A)  More information is needed. 
B)  25 W 
C)  200 W 
D)  100 W 
A)  More information is needed. 
B)  25 W 
C)  200 W 
D)  100 W

Exam 19: Magnetism Magnets: Part A

If a 500-W heater carries a current of 2.00 A,what is the voltage across the ends of the heating element?

An electric clothes dryer draws 20 A at 220 V.If the clothes put into the dryer have a mass of 7.0 kg when wet and 3.0 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,Lv = 2.26 × 106 J/kg. )

A water pump draws about 4.4 A when connected to 240 V.What is the cost (with electrical energy at 9 cents per kWh)of running the pump for 10 h?

An electric car is designed to run off a bank of 12-V batteries with total energy storage of 6.0 × 107 J.If the electric motor draws 6000 W in moving the car at a steady speed of 10 m/s,how far will the car go before it is "out of juice?"

In circuits involving resistors and capacitors the quantity 63% often arises.Which of the following is equivalent to this quantity?

A high voltage transmission line of diameter 2 cm and length 2 km carries a steady current of 1000 A.If the conductor is copper with a free charge density of 8 × 1028 electrons/m3,how long does it take one electron to travel the full length of the cable? (e = 1.6 × 10−19 C)

Five resistors each have resistance R.Three of the resistors are connected in series and this combination is then connected in parallel with the two other resistors which have been connected in series with each other.What is the equivalent resistance for this arrangement?

A tungsten wire is used to determine the melting point of indium.The resistance of the tungsten wire is 6.000 Ω at 20°C and increases to 9.700 Ω as the indium starts to melt.αtungsten = 4.50 × 10−3 (°C)−1.What is the melting temperature of indium?

A metal wire has a resistance of 10.00 Ω at a temperature of 20.0°C.If the same wire has a resistance of 10.55 Ω at 90°C,what is the resistance when its temperature is 0.0°C?

A 100-W light bulb is in a socket supplied with 120 V.What is the current in the bulb?

Two resistors of values 6.0 and 12.0 Ω are connected in parallel.This combination in turn is hooked in series with an 8.0-Ω resistor and a 24-V battery.What is the current in the 12-Ω resistor?

Three wires of the same diameter and length are made from three different metals: copper (ρ​ = 1.7 × 10-8 Ω·m),aluminum (ρ​ = 2.7 × 10-8 Ω·m),and silver (ρ​ = 1.6 × 10-8 Ω·m).Which wire has the least resistance?

A metal wire has a resistance of 25.00 Ω under room temperature conditions of 25°C.When the wire is heated to 85°C the resistance increases by 1.95 Ω.What is the temperature coefficient of resistivity of this metal?

A lightbulb drawing a current of 0.60 A is run for 2.0 hours.How many electrons pass through the bulb during this process?

How long is a wire made from 200 cm3 of copper if its resistance is 8.5 ohms? The resistivity of copper is 1.7 × 10-5 Ω·m.

What is the current through the 6-Ω resistor?

Three 3.0-Ω resistors are connected in parallel to a 12.0-V battery.What is the current in any one of the resistors?

A 100-W bulb and a 40-W bulb,each designed for an applied voltage of 120 V,are connected in series across a 120-V source.What are the voltages across the 100-W bulb and across the 40-W bulb?

A hair dryer draws 1500 W,a curling iron draws 800 W,and an electric light fixture draws 500 W.If all three of these appliances are operating in parallel on a 120 V circuit,what is the total current drawn?

If a light bulb has half the resistance of a 50-W lightbulb,what would be its wattage? Assume both bulbs are attached to the same 120-V circuit.

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

An electric clothes dryer draws 20 A at 220 V.If the clothes put into the dryer have a mass of 7.0 kg when wet and 3.0 kg dry,how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water,L_v = 2.26 × 10⁶ J/kg. )

An electric car is designed to run off a bank of 12-V batteries with total energy storage of 6.0 × 10⁷ J.If the electric motor draws 6000 W in moving the car at a steady speed of 10 m/s,how far will the car go before it is "out of juice?"

A high voltage transmission line of diameter 2 cm and length 2 km carries a steady current of 1000 A.If the conductor is copper with a free charge density of 8 × 10²⁸ electrons/m³,how long does it take one electron to travel the full length of the cable? (e = 1.6 × 10−¹⁹ C)

A tungsten wire is used to determine the melting point of indium.The resistance of the tungsten wire is 6.000 Ω at 20°C and increases to 9.700 Ω as the indium starts to melt.α_tungsten = 4.50 × 10−³ (°C)−¹.What is the melting temperature of indium?

Three wires of the same diameter and length are made from three different metals: copper (ρ = 1.7 × 10^-8 Ω·m),aluminum (ρ = 2.7 × 10^-8 Ω·m),and silver (ρ = 1.6 × 10^-8 Ω·m).Which wire has the least resistance?

How long is a wire made from 200 cm³ of copper if its resistance is 8.5 ohms? The resistivity of copper is 1.7 × 10^-5 Ω·m.