A nickel has a mass of 5 grams. If this mass could be converted completely into electrical energy, how long would it keep a 100 Watt light bulb lit?
1.4*10^5 years
To determine the time a nickel could keep a 100 Watt light bulb lit, we need to calculate the energy stored in the nickel and then divide it by the power consumption of the light bulb.
First, let's convert the nickel's mass from grams to kilograms since energy is typically measured in joules (J) and the standard unit of mass is kilogram (kg). So, the mass of the nickel is 0.005 kg (5 grams = 0.005 kg).
Next, we can use Albert Einstein's famous equation E=mc², where E is the energy, m is the mass, and c is the speed of light (approximately 3 x 10^8 m/s), to calculate the energy stored in the nickel:
E = mc²
E = (0.005 kg) x (3 x 10^8 m/s)²
E = (0.005 kg) x (9 x 10^16 m²/s²)
E = 4.5 x 10^14 J
Now that we have the total energy stored in the nickel, we can divide it by the power consumption of the light bulb (100 Watts) to determine the time it can keep the light bulb lit:
Time = Energy / Power
Time = (4.5 x 10^14 J) / (100 W)
Time ≈ 4.5 x 10^12 seconds
Therefore, a nickel, if completely converted into electrical energy, could keep a 100 Watt light bulb lit for approximately 4.5 trillion seconds.