p6 3.3

A +10μC point charge is 25cm away from a -20μC point charge. Calculate the magnitude of the electric force between them.

28.8 N

The electric force between two point charges with a magnitude of +800μC and +900μC is 15 N. How far apart are the two charges from each other in centimeters?

2.1cm

A force of 500 N exists between two identical point charges separated by a distance of 40 cm. Calculate the magnitude of the two point charges.

9.4 ⨯ 10⁻⁵ C

Two point charges +8μC and -5μC are separated by a distance of 10 cm What is the magnitude of the electrostatic force? Is the force repulsive for attractive?

36 N, attractive

How many electrons represent a charge of -70μC?

4.375 ⨯ 10¹⁴ electrons

What is the electric charge in μC of 5 ⨯10¹⁴ protons?

80μC

A metal sphere has 4.3 ⨯10²¹ protons and 6.8 ⨯10²¹ electrons. What is the net electric charge on the metal spheres?

-400 C

A +100μC is placed at the origin. A -50μC is placed at 2 m and a +200μC is placed at -4 m. What is the net electric force acting on 100μC?

22.5 N

A charge of 6μC exerts a force of 2.4 ⨯10⁻⁴ in the right side while positive test charge. What is the magnitude and direction of electric field at the location of the test charge?

40 N/C

What is the magnitude and direction of the electric field 0.10 meters on the left hand of a -4.2μC charge?

-3780000 N/C

Two charges -2 ⨯10⁻⁷C and 3.4 ⨯10⁻⁷C are 4m apart What is the magnitude and direction of the electric field at a point midway between the two charges?

-1215 N/C, left

Calculate the potential energy of point A

80J

Calculate the potential energy of point B

20J

How much work is done to move the charge from point A to point B?

60J

What is the electric potential of point A

1.6 ⨯ 10⁶ V

What is the electric potential of point B

4 ⨯ 10⁵ V

what is the electronic potential energy of point X

22.5J

What is the electric potential energy of point Y

4.5J

How much work is done to move the charge from point X to point Y

18J

What is the electric potential of X

7.5 ⨯ 10⁵ V

What is the electric potential of point Y

1.5 ⨯ 10⁵ V

5 A

A rice cooker uses 500 watts of power in Japan what is the current flowing through the appliance?

1440 W

A small space heater draws 12 A of current in the USA. What is the power used by the heater?

4 A

A fad has a resistance of 25 Ω and is plugged into a Japanese outlet. What is the current across the fan?

480 W

A microwave oven has a resistance of 30 Ω. What is the power when it is plugged into a 120V source?