What is the main optical element of a refractor telescope?
A. lens.
B. mirror.
C. combination of many small plane mirrors.
D. prism of glass.
Answer: A. lens.
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In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct?
a. The system lost 800 J by heat transfer to its surroundings. b. The system gained 800 J by heat transfer from its surroundings. c. The system performed 800 J of work on its surroundings. d. The surroundings performed 800 J of work on the system. e. The 800 J of work done by the system was equal to the 800 J of heat transferred to the system from its surroundings.
Light takes about 8 minutes to travel from the Sun to Earth and about 40 minutes to travel from the Sun to Jupiter. Jupiter is about ____________________ AU from the Sun
Fill in the blank(s) with correct word
If M = 1.1 kg, what is the tension in string 1?
A. 54 N B. 47 N C. 40 N D. 62 N E. 57 N
You leave a black, spherical bowling ball out in the hot sun and it warms to a scalding hot temperature of 80ºC. The ball has a radius of 0.25 m (25 cm). What is the total power being radiated outward from this hot ball at this temperature?