P6 - Electricity for gadgets.

Resisting

• What happens to the brightness of a bulb if the resistance in the ciruit is increased?
• What happens to the resistance of a wire if its cross-sectional area increases?
• A car headlamp bulb has a resistance of 6Ohms. Calculate the current when the voltage is 12V

Sharing

• A potential divider ciruit is made from two identical resistors. The input it 12V, what is the possible output ?
• A 200 and 600Ohm resistor are used in a potential divider circuit. Calculate the output voltage across the 600Ohm resistor when the voltage is 240V

Resisting

• Decreases/dimmer.
• Decreases
• 2A

Sharing

• 0V; 6V or 12V.
• 180V.

Motoring

• Alex uses his right hand to predict how a motor will spin. He points his first finger in the direction of the field and his second finger in the direction of the current. In which direction is his thumb pointing?
• What is the job of the brushed in an electric motor?
• Write down two advantages of curved poles in a motor.

Generating

• John moves a magnet into a coil slowly and removes it quickly. Describe the differences in the current produced in the coil.
• What happens to the current in the stator coild and frequency of the current if the turbine rotor coils faster?
• What is the job of the slip rings?

Motoring

• Oppostie direction to the motion.
• Deliever current to communitator.
• Increases force; keeps the force constant.

Generating

• Current when removing the magnet is greater and in the opposite direciton.
• Current increases; frequency is higher.
• Allow coil to spin without wires twisting around each other.

Transforming

• Name one other device that works because a changing magnetic field induces a current in a wire.
• The current in a wire is increased from 1 to 3A. By how much is the power loss increased?
• A portable generate has a power rating of 1840W. The output is 230V. Calculate the maximum current.

Charging

• What information does the current -voltage graph for a diode provide about the resistance of the diode when ir is reverse biased or forward biased?
• Explain the difference between the abction of a battery and of a capacitor.

Transforming

• Dynamo/generator
• 9 times
• 8A.

Charging

• Resistance is very high or resistance is very low.
• Battery contains chemicals which produce electrical energy. Capacitor does not produce electrical energy, it stores charge.