A Geiger counter registers a count rate of 8,000 counts per minute from a sample of a radioisotope. The count rate 24 minutes later is 1,000 counts per minute. What is the half-life of the radioisotope?
8 minutes
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A hockey puck slides off the edge of a table with an initial velocity of 20.0 m/s. The height of the table above the ground is 2.0 m. What is the magnitude of the vertical component of the velocity of the puck just before it hits the ground?
A) 20.0 m/s B) 6.26 m/s C) 12.5 m/s D) 19.6 m/s E) 21 m/s
Mapping the intracluster gas is largely done with red light from the ionized emission lines of hot hydrogen
Indicate whether the statement is true or false
What is the angular momentum of the Moon about the Earth? The mass of the Moon is 7.35 × 10^22 kg, the center-to-center separation of the Earth and the Moon is 3.84 × 10^5 km, and the orbital period of the Moon is 27.3 days. Ignore the small offset of the center of mass of the system from the center of the Earth in your calculation
A certain photon after being scattered from a free electron at rest moves at an angle of 120° with respect to the incident direction. The wavelength of the incident photon is 0.651 nm
(a.) What is the wavelength of the scattered photon? (b.) What is the energy of the scattered photon?