When it is struck by 240-nm photons, a material having a work function of 2.60 eV emits electrons. What is the maximum kinetic energy of the emitted electrons?
(c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ? s, 1 eV = 1.60 × 10-19 J)
A) 2.58 eV
B) 5.18 eV
C) 2.00 eV
D) 4.21 eV
A
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A 2.0-kg mass is projected vertically upward from ground level with an initial speed of 30 m/s. The mass rises to a maximum height of 35 m above ground level. What is the change in mechanical energy of the mass caused by air resistance between the point of projection and the point of maximum height?
a. -0.21 kJ b. -0.47 kJ c. -0.40 kJ d. -0.34 kJ e. -0.69 kJ
Of all the planets known in antiquity, ________ is the hardest to observe visually
Fill in the blank(s) with correct word
From the point of view of an observer on the Earth, a muon produced high in the atmosphere can reach the ground before decaying because
a. relativity gives it extra time to get there. b. of the uncertainty principle. c. it is a short distance to the ground. d. relativity shortens the distance to the ground.
Consider a collection of charges in a given region and suppose all other
charges are distant and have a negligible effect. Further, the electric potential is taken to be zero at infinity. If the electric potential at a given point in the region is zero, which of the following statements must be true? (a) The electric field is zero at that point. (b) The electric potential energy is a minimum at that point. (c) There is no net charge in the region. (d) Some charges in the region are positive, and some are negative. (e) The charge shave the same sign and are symmetrically arranged around the given point.
1.(a) only 2.(d) only 3.(b), (c), and (d) 4.(a) and (e)