What makes us think that the star system Cygnus X-1 contains a black hole?
A) It emits x-rays as we expect from a system with an accretion disk, but the unseen star in the system is too massive to be a neutron star.
B) No light is emitted from this star system, so it must contain a black hole.
C) The fact that we see strong x-ray emission tells us that the system must contain a black hole.
D) Cygnus X-1 is a powerful x-ray burster, so it must contain a black hole.
A) It emits x-rays as we expect from a system with an accretion disk, but the unseen star in the system is too massive to be a neutron star.
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In a double-slit experiment, the distance between the slits is 0.2 mm and the distance to the screen is 100 cm. What is the phase difference (in degrees) between the waves from the two slits arriving at a point 5 mm from the central maximum when the wavelength is 400 nm? (Convert your result so the angle is between 0 and 360°.)
a. 90° b. 180° c. 270° d. 360° e. 160°
Uniform Electric Fields: A space probe approaches a planet, taking measurements as it goes. If it detects a potential difference of 6000 MV between the altitudes of 253,000 km and 276,000 km above the planet's surface, what is the approximate electric field strength produced by the planet at 264,500 km above the surface? Assume the electric field strength is approximately constant at these altitudes.
A. 261 N/C B. 0.261 N/C C. 561 N/C D. 493 ?N/C
A capacitor C is connected in series with a resistor R across a battery and an open switch. If a second capacitor of capacitance 2C is connected in series with the first one, the time constant of the new RC circuit will be
A) smaller than before. B) larger than before. C) the same as before. D) variable.
Objects that subtend a larger angle in the eye
A. Are perceived to be smaller B. Are perceived to be larger C. The subtended angle has no effect on perception D. Are farther way