Which kind of object is the best standard candle for measuring distances to extremely distant galaxies?
A. a white dwarf.
B. a Cepheid variable star.
C. a white dwarf supernova.
Answer: C. a white dwarf supernova.
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Which of these elements had to be made in a supernova explosion?
a) calcium b) uranium c) oxygen
A rock sample contains 1/8 micrograms of the parent radioactive isotope Al-26 and 7/8 micrograms of its daughter isotope Mg-40. If the half-life of this decay is approximately 700,000 years, how old is this rock?
A) 2.1 million years B) 2.8 million years C) 1.4 million years D) 700,000 years
An electron in a cathode ray tube is accelerated through a potential difference of 10 kV. What kinetic energy does the electron gain in the process? (e = 1.6 × 10^-19 C)
a. 8.0 × 10^-16 J c. 8.0 × 10^22 J b. 1.6 × 10^-15 J d. 1.6 × 10^-16 J
Telephones don't transmit frequencies above 3,400 Hz. Musical notes should sound normal over the telephone as long as they are below 3,400 Hz
Indicate whether the statement is true or false