APES Energy Math

If a 100 W incandescent bulb uses 400 kJ of energy per hour. How much would a CFL use that is 3 times as efficient IN 30 MINUTES?

• 66 kJ
• 133 kJ
• 200 kJ
• 1200 kJ

One gallon of fuel produces 5 lbs of CO2. Two cars drive 100 miles each. The first gets 10 MPG. The second gets 25 MPG. How much LESS CO2 is produced by the second car?

• 10 pounds
• 50 pounds
• 30 pounds 
• 15 pounds

Tags

NGSS.MS-PS3-5

Strontium-90 has a half-life of 29 years. If a site held 2000 kg of this isotope, approximately what mass of Strontium-90 would be left after 116 years?

• 1000 kg
• 500 kg
• 250 kg
• 125 kg

Tags

NGSS.HS-PS1-8