Physics quiz

What is Ohm’s law?

1.     What is the voltage of a circuit with 15 amps of current and toaster with 8 ohms of resistance?

2.      A light bulb has a resistance of 4 ohms and a current of 2 A. What is the voltage across the bulb?

3.     How much voltage would be necessary to generate 10 amps of current in a circuit that has 5 ohms of resistance?

4.     What is a series circuit?

5.     Define parallel circuit?

6.     Calculate the total resistance of a circuit containing each of the following combinations of resistors.

a. Two 8 Ω resistors in parallel

b. Two 12 Ω resistors in parallel

c. A 4 Ω resistor and an 8 Ω resistor in parallel

d. A 12 Ω resistor and a 3 Ω resistor in parallel

7.     Electrical power

Your oven has a power rating of 5000 watts.

a. How many kilowatts is this?

b. If the oven is used for 2 hours to bake cookies, how many kilowatt-hours (kWh) are used?

c. If your town charges $0.15/kWh, what is the cost to use the oven to bake the cookies?

8. Coulomb’s Law

a. What is the force between a 3 C charge and a 2 C charge separated by a distance of 5 meters?

b. Calculate the force between a 0.006 C charge and a 0.001 C charge 4 meters apart.

c. Calculate the force between a 0.05 C charge and a 0.03 C charge 2 meters apart.

Physics SG

PHYSICS   STUDY GUIDE

CLASS PRACTICE PROBLEMS

 Boyle’s Law

 1) If I have 5.6 liters of gas in a piston at a pressure of 1.5 atm and compress the gas until its volume is 4.8 L, what will the new pressure inside the piston be?

2) I have added 15 L of air to a balloon at sea level (1.0 atm). If I take the balloon with me to Denver, where the air pressure is 0.85 atm, what will the new volume of the balloon be?

3) I’ve got a car with an internal volume of 12,000 L. If I drive my car into the river and it implodes, what will be the volume of the gas when the pressure goes from 1.0 atm to 1.4 atm?

Boyle’s Law:

 When ____________ is held constant, the pressure and volume of a gas are ____________ proportional.

2. Mathematically, Boyle’s law is stated PV = ____________ or P1V1 = ____________. 3. At a pressure of 405 kPa, the volume of a gas is 6.00 cm

3 . Assuming the temperature remains constant, at what pressure will the new volume be 4.00 cm3 ?

Remember: Heat energy can be “spent” on only one job at a time.  Either it will cause a change in temperature or change of state.  Each must be calculated separately.

c_(ice) = 2.06 J/g°C,    c_(H2O) = 4.184 J/g°C,    c_(steam) = 1.87 J/g°C,  

DH_(fus) for H₂O is 334.J/g,     DH_(vap) for H₂O is 2260 J/g

1.     What is the molar heat of solidification for water?

2.     How much energy is released to the environment by 50.0 grams of condensing water vapor?

3.     Is melting endothermic or exothermic? Explain.

4.     Calculate the amount of heat needed to melt 35.0 g of ice at 0 ºC. Express your answer in kilojoules.

5.     Calculate the amount of heat needed to convert 190.0 g of liquid water at 18 ºC to steam at 100. ºC. (two calculations!).

6.     Calculate the amount of heat needed to convert 96 g of ice at –24 ºC to water at 28 ºC. (figure out how many steps first and be sure to use correct specific heats)

7.     Calculate the amount of heat released to the environment as 245 g of steam at 140 ºC is cooled to –15 ºC. (go for it!)

Specific heat
1. A 0.5-kilogram piece of aluminum increases its temperature 7°C when heat energy is added. How much heat
energy produced this change in temperature?
2. A volume of water has a mass of 0.5 kilogram. If the temperature of this amount of water was raised by 7°C,
how much heat energy is produced?
3. How much heat energy is required to raise the temperature of 1 kilogram of steel by 10°C?
4. How much heat energy is needed to raise the temperature of 100-liters of water from 10°C to 25°C? Note:
One liter of water has a mass of one kilogram.
5. When 1,500 joules of energy is lost from a 0.12-kilogram object, the temperature decreases from 45°C to

40°C. What is the specific heat of this object? Of what material is the object made?

DENSITY
A solid rubber stopper has a mass of 33.0 grams and a volume of 30.0 cm3. What is the density of rubber?
2. A chunk of paraffin (wax) has a mass of 50.4 grams and a volume of 57.9 cm3. What is the density of
paraffin?
3. A marble statue has a mass of 6,200 grams and a volume of 2,296 cm3. What is the density of marble?
4. The density of ice is 0.92 g/cm3. An ice sculptor orders a one cubic meter block of ice. What is the mass of
the block? Hint: 1 m3 = 1,000,000 cm3. Give your answer in grams and kilograms.
5. What is the mass of a pure platinum disk with a volume of 113 cm3? The density of platinum is 21.4 g/cm3.
Give your answer in grams and kilograms.

Charles' law
1. If a truck tire holds 25.0 liters of air at 25.0°C, what will be the volume of air in the tire if the temperature
increases to 30.0°C?
2. A balloon holds 20.0 liters of helium at 10.0°C. If the temperature increases to 50.0°C, and the pressure does
not change, what will be the new volume of the balloon?

Einstein’s Formula
1. How much energy is contained in matter with a mass of 1 gram (0.001 kilogram)?

2. How much energy is contained in the mass of a 60-kilogram person?

Ohm's Law
1. How much current is in a circuit that includes a 9-volt battery and a bulb with a resistance of 3 ohms?
2. How much current is in a circuit that includes a 9-volt battery and a bulb with a resistance of 12 ohms?

3. A circuit contains a 1.5 volt battery and a bulb with a resistance of 3 ohms. Calculate the current.
Series Circuits