A small bulb is rated at 7.5 W when operated at 125 V. Its resistance (in ohms) is

a. 0.45.
b. 7.5.
c. 17.
d. 940.
e. 2 100.


e

Physics & Space Science

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A point charge is located at the origin. Centered along the x axis is a cylindrical closed surface of radius 10 cm with one end surface located at x = 2 m and the other end surface located at x = 4 m. If the magnitude of the electric flux through the surface at x = 2 m is 4 N ? m2/C, what is the magnitude of the electric flux through the surface at x = 4 m?

A. 1 N ? m2/C B. 2 N ? m2/C C. 4 N ? m2/C D. 16 N ? m2/C E. The correct value is not given.

Physics & Space Science

The image of our galaxy in radio emission from carbon monoxide maps the distribution of molecular clouds. Which of the following would give a similar picture of our galaxy?

A) visible light, which is closest to how the night sky appears from Earth B) 21-cm-line radio emission from atomic hydrogen C) X-rays from hot gas bubbles in the disk D) infrared emission from interstellar dust grains E) visible light, showing the edges of supernova bubbles

Physics & Space Science

The average density of neutron stars approaches:

A) a million times that of normal matter. B) a million times that of even a white dwarf. C) about 1017 kg/m3, similar to the density of atomic nuclei. D) about 1018 times that of water. E) infinity.

Physics & Space Science

In Jules Verne's From the Earth to the Moon, scientists are launched from the surface of Earth by a cannon

With what speed would their capsule have to leave the cannon if the speed of the capsule is required to be zero m/s at the point between Earth and the Moon where their gravitational pulls on the capsule are equal? The mass of Earth is 5.97 × 1024 kg, the mass of the Moon is 7.35 × 1022 kg, the distance between Earth and the Moon is 3.84 × 108 m, the radius of Earth is 6.37 × 106 m, and G = 6.67 x 10-11 N•m2/kg2. A) 11,100 m/s B) 11,200 m/s C) 10,400 m/s D) 15,700 m/s E) 15,800 m/s

Physics & Space Science