Matter Waves: If the de Broglie wavelength of an electron is 2.4 ?m, what is the speed of the electron? (melectron = 9.11 × 10-31 kg, h = 6.626 × 10-34 J ? s)
A. 3.0 × 102 m/s
B. 2.5 × 105 m/s
C. 1.7 × 103 m/s
D. 8.3 × 106 m/s
Answer: A
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Charge A has 10 electric field lines coming out, charge B has 20 lines coming out, and charge C has 30 lines coming in. Which pair of these charges will have the largest force between them if placed one cm apart?
a. A and B c. More information is needed. b. B and C d. C and A
In which of the following processes does the system's total mass change?
A) An automobile speeds up. B) A rubber ball is squeezed. C) The total mass changes in both of the above processes. D) The total mass changed in neither of the above processes.
Equilibrium: A uniform ladder 12 meters long rests against a vertical frictionless wall, as shown in the figure. The ladder weighs 400 N and makes an angle ? = 51° with the floor. A man weighing 874 N climbs slowly up the ladder. When he is 78 m from the bottom of the ladder, it just starts to slip. What is the coefficient of static friction between the floor and the ladder?
Fill in the blank(s) with the appropriate word(s).
Photon Momentum: What is the momentum of a photon of light that has a frequency of 2.8 × 1014 Hz? (c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ? s)
A. 1.5 × 1028 kg?m/s B. 2.1 × 1028 kg?m/s C. 4.4 × 1028 kg?m/s D. 6.3 × 1028 kg?m/s E. 6.2 × 1028 kg?m/s