What did Becquerel discover about uranium?
a. That some uranium salts fluoresced in sunlight.
b. That all uranium salts fluoresced in sunlight.
c. That X rays striking some uranium salts produced visible light.
d. That fluorescent light can pass right through the light proof covering used then for photographic plates.
e. That all uranium salts would expose photographic film with or without exposure to light.
e
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Consider a 1000. Gauss magnetic field along the z axis and a proton moving with an instantaneous velocity of = 3 + 4 km/s (note its speed is 5. km/s composed of 3. km/s along the x axis and 4. km/s along the z axis)
Determine the radius of its spiraling orbit. [proton: 1.67 × 10-27 kg and 1.6 × 10-19 Coulomb]
Planet W-70 has a radius of 2.48 × 107 m and an escape velocity of 23,300 m/s. What is the mass of W-70? (G = 6.67 × 10-11 N ? m2/kg2 )
A) 1.01 × 1026 kg B) 2.02 × 1026 kg C) 3.03 × 1026 kg D) 4.04 × 1026 kg E) 5.05 × 1026 kg
The objective lens of a refracting astronomical telescope has a focal length of 60 cm, and the eyepiece has a focal length of 2.0 cm. How far apart should the lenses be placed in order to form a final image at infinity?
A) 60 cm B) 58 cm C) 76 cm D) 44 cm E) 62 cm
Radio astronomers often study the radiation emitted by a hydrogen atom from a transition between the two hyperfine levels associated with the ground state. This radiation has a wavelength of 21 cm
What is the energy difference between the hyperfine levels? (1 eV = 1.60 × 10-19 J) A) 5.9 × 10-6 eV B) 5.9 × 10-25 J C) 1.7 × 10-24 J D) 4.7 × 10-25 J