Math for APES

If an incandescent light bulb used for lighting has an efficiency rating of 5 percent, then for every 1.00 joules of electrical energy consumed by the bulb, which of the following is produced? (Energy)

• 1.05 joules of light energy

• 1.05 joules of heat energy

• 0.95 joules of light energy

• 0.05 joule of light energy

• 0.05 joule of heat energy

Tags

NGSS.HS-PS3-4

A sample of radioactive waste has a half-life of 10 years and an activity level of 2 curies. After how many years will the activity level of this ample be 0.25 curie? (Half-life)

• 10 years

• 20 years

• 30 years

• 40 years

• 80 years

Tags

NGSS.HS-PS1-8

I-131 has a half life of about 8 days. if an original sample weights 240kg, how many kg will remain after 32 days? (Half-life)

• 15

• 30

• 45

• 60

• 120

Tags

NGSS.HS-PS1-8

You have a TV that uses 30 w of power when not turned on but still plugged in. The TV is turned on 4 hours a day. When the TV is not turned on, it is left plugged into the electrical outlet. How many kWh are used a day for the turned off TV left plugged in?

• .6 kwh/day

• 600 kwh/day

• 60 kwh/day

• 720 kwh/day

You are always cold, always. Your electric blanket uses 400 watts of energy. You use it all 8 hours that you sleep, because sleep must not be neglected. Let’s say a year is 300 days. How many kwh do you use per year?

• 2400 kwh/year

• 3200 kwh/year

• 960 kwh/year

• 96 kwh/year