6.6- 6.9

What is a disadvantage of using nuclear energy as a source of electricity

-waste is radioactive and disposal is expensive -Local thermal pollution can harm aquatic life -Spent fuel rods must be disposed of properly

A 2.5 gram sample of an isotope of Strontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson Island in the Pacific Test Site. The half-life of Strontium-90 is 28 years. In what year did only 0.625 grams of this Strontium-90 remain?

0.693

Economic benefits of building large dams include which of the following? I. Storage of water for agriculture and domestic use. II. Controlling floods upstream. III. Production of renewable energy

1 and 3

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 sample be 0.25 curie?

30 years

An isotope of Cesium-137 has a half life of 30 years. If 35.0 mg Cesium 137 disintegrates over a period of 90 years, how many mg of Cesium 137 would remain

4.375 mg

After 200 million years, only 1/16 of the original amount of a particular radioactive waste will remain. The half-life of this radioactive waste is how many million years?

50 million years

where does fusion occur

Attaching, adding together, possible on the sun, not possible yet

Throughout the world, especially the less-developed countries, burning wood or other biomass for heating or cooking in homes is common. One negative environmental impact of this practice is the production of particulates indoors, which can be a health hazard to humans.What is the best strategy for mitigating this potential problem?

Better ventilation systems

What is the most successful solution to the problem of fish mortality caused by dams?

Building fish ladders around the dam.

Describe an advantage of burning biomass rather than burning fossil fuels in developing countries

Cheaper than fossil fuel extractio making it more readily available for use

The largest hydroelectric dam in the world is located on one of the world's longest rivers in which country? Give the letter and name it.

China E

A developer intends to use passive solar heating in a new construction project in Minnesota in an effort to reduce electricity costs for the property owners. What should be employed to maximize the benefit of passive solar heating?

Concentrate the energy on the roof using mirrors to heat water that is then used to generate electricity

Many environmentalists consider Egypt's Aswan High Dam on the Nile River to be an ecological disaster. Why?

Most of the nutrient-rich silt that the Nile annually deposited downstream is now deposited behind the dam.

where does fission occur

Splitting appart, possible

Describe how electricity is generated using photovoltaic cells?

energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow

The water used in a nuclear power plant is often released back into a reservior. What effects could this released water have on the reservoir?

low dissolved oxygen, altered food web, decreased fish population, suffocated fish

What process would provide the energy used to generate electricity at a power plant?

nuclear fission

What was the primary cause for the decline in the use of wood as a fuel in the eighteen hundreds

reduced wood availability resulting from widespread deforestation

Some solar energy systems produce high-temperature water for industrial applications and produce steam to run turbines that generate electricity. What type of solar energy system is needed for these kinds of applications?

solar thermal electric generation systems using mirrors or lenses to concentrate sunlight to heat water.

Buildings designed to partially heat rooms by passive solar heating rely on what?

the position of the sun

What is a major limitation of using photovoltaic cells to generate electricity?

the quality of solar power radiation on it, as different times brings different power density.

What is a drawback to using biofuels, such as ethanol, as a fuel source?

there is high energy investment in producing and processing the crops needed for ethanol production

What is a negative consequence associated with photovoltaic solar cells?

wastewater and waste gas pollutions