A Gamma-Ray Burst (GRB), Such as the One in the Figure

question 91

Multiple Choice

A gamma-ray burst (GRB) , such as the one in the figure below, may be responsible for some of Earth's mass extinctions.GRBs are hard to study because they

• A) can only happen in distant galaxies.
• B) are rare, of short duration, and very narrow.
• C) emit very few gamma rays.
• D) only generate gravitational waves.
• E) are long-lived but rotating.

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Definitions:

Present Value

The current value of a future amount of money or stream of cash flows, given a specified rate of return.

Rate Of Return

The increase or decrease in value of an investment within a set timeframe, represented as a percentage of the investment's starting price.

Discount Rate

The interest rate charged by central banks on loans they give to commercial banks or the rate used to discount future cash flows to their present value.

Present Value

The worth in present terms of a lump sum or cash flows anticipated in the future, using a predetermined rate of return for the calculation.