The Planck time is
A) the shortest time that has any physical meaning.
B) the time required for pair creation.
C) the time it takes for light to travel across--or around--the entire universe.
D) the time when the cosmic background radiation originated.
E) the time it takes for an electron in an unexcited hydrogen atom to orbit the nucleus one time.
A
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Besides Earth, which of the terrestrial planets and/or satellites of terrestrial planets show(s) evidence for the possible existence of liquid water flowing on its surface in the past?
a. Venus b. The Moon c. Phobos d. Mars e. None of the terrestrial planets or satellites show such evidence.
Equilibrium: A 3.00-m-long ladder, weighing 200 N, leans against a smooth vertical wall with its base on a horizontal rough floor, a distance of 1.00 m away from the wall. The ladder is not completely uniform, so its center of gravity is 1.20 m from its base. What force of friction must the floor exert on the base of the ladder to prevent the ladder from sliding down?
A. 93.3 N B. 130 N C. 28.3 N D. 102 N E. 150 N
If the radiant energy from the sun comes in as a plane EM wave of intensity 1340 W/m2, calculate the peak values of E and B
a. 300 V/m, 10?4 T b. 1 000 V/m, 3.35 × 10^?6 T c. 225 V/m, 1.60× 10?3 T d. 111 V/m, 3.00 × 10^?5 T e. 711 V/m, 2.37 × 10^?6 T
Earthquake waves are classified as P waves and S waves. Which of the following statements is true about these waves?
a. The P wave is transverse as is the S wave. b. The P wave is longitudinal as is the S wave. c. The P wave is transverse and the S wave is longitudinal. d. The P wave is longitudinal and the S wave is transverse. e. Both the P and S waves are mixtures of longitudinal and transverse waves.