The atomic number of uranium-235 is 92, its half-life is 704 million years and the radioactive decay of l kg of 235U releases 6.7X10^13 J. Generally, radioactive material is considered safe after 10 half-lives.

Assume that a nuclear powerplant can convert energy from 235U into electricity with an efficiency of 35%, the electrical transmission lines operate at 90% efficiency, and flourescent lights operate at 22% efficiency.

1.) What is the overall efficiency of converting the energy of 235U into flourescent light?

2.) How much energy from 1 kg of 235U is converted into flourescent light?

Question

Physics

Gemma

23 March, 08:28

The atomic number of uranium-235 is 92, its half-life is 704 million years and the radioactive decay of l kg of 235U releases 6.7X10^13 J. Generally, radioactive material is considered safe after 10 half-lives.

Assume that a nuclear powerplant can convert energy from 235U into electricity with an efficiency of 35%, the electrical transmission lines operate at 90% efficiency, and flourescent lights operate at 22% efficiency.

1.) What is the overall efficiency of converting the energy of 235U into flourescent light?

2.) How much energy from 1 kg of 235U is converted into flourescent light?

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Answers (1)

Know the Answer?

Hailey Neal · Answer 1

1) Let us say that x energy is available in the Uranium.

Conversion to electricity: 0.35x

Transmission efficiency = 0.9 x 0.35 = 0.315x

Light efficiency = 0.22 x 0.315x = 0.0693x

Overall efficiency = 0.0693 * 100 = 6.93%

2) Energy released = 6.7 x 10¹³ J

Energy converted = 6.7 x 10¹³ x 0.0693

= 4.64 x 10¹² Joules