Questions from College Physics

Q: A platinum resistance thermometer has resistances of 200.0 Ω when

A platinum resistance thermometer has resistances of 200.0 Ω when placed in a 0°C ice bath and 253.8 Ω when immersed in a crucible containing melting potassium. What is the melting point of potassium?...

Q: A 5.00 - V power supply provides a maximum current

A 5.00 - V power supply provides a maximum current of 10.0 A. (a) Calculate the maximum power delivered by the power supply. (b) How many 2.00 - W cell phone chargers could be powered by the power sup...

Q: If electrical energy costs $0.12 per kilowatt - hour

If electrical energy costs $0.12 per kilowatt - hour, how much does it cost to (a) Burn a 100 - W light-bulb for 24 h? (b) Operate an electric oven for 5.0 h if it carries a current of 20.0 A at 220 V...

Q: A 1.50-kg iron horseshoe initially at 600°

A 1.50-kg iron horseshoe initially at 600°C is dropped into a bucket containing 20.0 kg of water at 25.0°C. What is the final temperature of the water–horseshoe system? Ignore the heat capacity of the...

Q: Residential building codes typically require the use of 12 - gauge copper

Residential building codes typically require the use of 12 - gauge copper wire (diameter 0.205 cm) for wiring receptacles. Such circuits carry currents as large as 20.0 A. If a wire of smaller diamete...

Q: A portable coffee heater supplies a potential difference of 12.0

A portable coffee heater supplies a potential difference of 12.0 V across a Nichrome heating element with a resistance of 2.00 Ω. (a) Calculate the power consumed by the heater. (b) How many minutes w...

Q: The heating element of a coffeemaker operates at 120. V and

The heating element of a coffeemaker operates at 120. V and carries a current of 2.00 A. Assuming the water absorbs all the energy converted by the resistor, calculate how long it takes to heat 0.500...

Q: A typical lightning bolt may last for 0.200 s and

A typical lightning bolt may last for 0.200 s and transfer 1.00 x 1020 electrons. Calculate the average current in the lightning bolt.

Q: A typical cell phone consumes an average of about 1.00

A typical cell phone consumes an average of about 1.00 W of electrical power and operates on 3.80 V. (a) What average current does the phone draw from its battery? (b) Calculate the energy stored in a...

Q: Light-bulb A is marked “25.0 W 120

Light-bulb A is marked “25.0 W 120. V,” and light-bulb B is marked “100. W 120. V.” These labels mean that each light-bulb has its respective power delivered to it when it is connected to a constant 1...