What is the maximum velocity of a photoelectron emitted from a surface with work function 5.22 eV when illuminated by 200-nm ultraviolet light? (melectron = 9.11 × 10^-31 kg, h = 6.63 × 10^-34 J×s, 1 eV = 1.60 × 10^-19 J, and 1 nm = 10-9 m)
a. 800,000 m/s
c. 653,000 m/s
b. 212,000 m/s
d. 591,000 m/s
D
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The objective and the eyepiece of a microscope have focal lengths of 4.00 mm and 25.0 mm, respectively. The objective produces a real image 30 times the size of the object
The final image is viewed at infinity, and the near point of the microscope user is at 25.0 cm. What is the distance between the object and the focal point of the objective? A) 0.13 mm B) 0.18 mm C) 0.23 mm D) 0.28 mm E) 0.33 mm
The spacing of ruled lines on a diffraction grating is 1,770 nm. The grating is illuminated at normal incidence with a parallel beam of white light in the 400 nm to 700 nm wavelength band
The longest wavelength that appears in the third order spectrum is closest to: A) 590 nm B) 570 nm C) 550 nm D) 530 nm E) 610 nm
As shown below, a square loop of wire of side a moves through a uniform magnetic field of magnitude B perpendicular to the page at constant velocity
directed to the right. Judd says that the emf induced in the loop is zero. Roger claims that it has magnitude 
. Which one, if either, is correct, and why?
?
?
?
a.
Judd, because the magnetic flux through the loop is constant.
b.
Roger, because the magnetic flux through the loop is constant.
c.
Judd, because the magnetic flux through the loop is not constant if 
.
d.
Roger, because the magnetic flux through the loop is not constant if 
.
e.
Roger, because the magnetic flux through the loop is ?B = 0.
If astronauts could travel at v = 0.90c, we on Earth would say it takes (4.2/0.90) = 4.7 years to reach Alpha Centauri, 4.2 lightyears away. The astronauts disagree. How much time passes on the astronaut's clocks?
a. 2.0 years c. 1.4 years b. 2.4 years d. 3.0 years