Assume that the nutritional content of an apple-say, 50 Cal (1 Cal = 1000 cal) - could be used to light a light bulb. For how many minutes would there be light from each of the following? (a) A 100-watt incandescent bulb (1 W = 1 J/s)

Video transcript

hi everyone for this problem it reads. The human heart produces 4680 jewels of energy and one hour assume that this energy can be used to light a fluorescent lamp for how many minutes is this energy sufficient to light a watt fluorescent lamp? One watt equals one jewel per second. So the question that we want to answer here is for how many minutes? Okay, is this energy sufficient to light a 25 watt fluorescent lamp? So what's our starting point? Our starting point is jewels. So we have 4680 jewels and our goal is to go from this number two minutes. Okay. And so we're going to need a couple of conversions here and the first one we're told one watt is equal to one jewel second and we have a 25 watt fluorescent lamp. So if one watt Is equal to one jewel per second, if we have a 25 watt fluorescent lamp, that means this equals jewels per second. Alright, so the first thing that we're going to want to do is we're going to want to go from jules two seconds and that is the conversion that we can use. So if we go here we can write there are jewels in one second for this fluorescent lamp. Okay, so our units for jewels cancel and now we're left in the units of seconds. But the question asks us for how many minutes. So now we need to go from seconds to minutes. Okay and we can write that in one minute. There is 60 seconds. Alright, So let's go ahead and put this conversion in in one minute, There is 60 seconds. So now our units four seconds cancel and we're left with units of minutes. Alright. So I wrote out seconds for one of them and I wrote out just the s so let's make this match. Okay, so one minute Is 60 seconds. So now we're left with units of minutes so now we can do the calculation. So we'll take 4680 jewels divided by 25 and then divide again by 60. And the answer we're going to get is 3. minutes. So our final answer for this problem is the time and minutes is going to equal 3.12 minutes. Okay, and this is going to be our final answer that is it for this problem. I hope this was helpful.