New surveys suggest brown dwarfs, stars under the critical mass for stable fusion, are probably very rare.

Answer the following statement true (T) or false (F)


False

Physics & Space Science

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In the proton-proton chain

a. no neutrinos are produced. b. energy is released because a helium nucleus has a greater mass than a hydrogen nucleus. c. no photons are produced. d. carbon serves as a catalyst for the nuclear reaction. e. energy is produced in the form of gamma rays and the velocity of the created nuclei.

Physics & Space Science

One mole of hydrogen, one mole of nitrogen and one mole of oxygen are held in a 22.4 × 10^3 cm3 enclosed vessel at 20°C. The pressure in the vessel, in N/m2, is

a. 109. b. 304. c. 326. d. 1.09 × 10^5. e. 3.26 × 10^5.

Physics & Space Science

The radius of the Sun is 6.95 × 108 m. It radiates heat at the rate of 5.32 x 1026 W. Assuming that it is a perfect emitter, what is the temperature of the surface of the Sun? The Stefan-Boltzmann constant is 5.67 x 10-8 W/(m2•K4)

A) 6.27 × 103 K B) 8.25 × 103 K C) 8.87 × 103 K D) 3.93 × 107 K E) 5.78 × 107 K

Physics & Space Science

A magnetic field is directed out of the page. Two charged particles enter from the top and take the paths shown in the figure. Which statement is correct?



a.
Particle 1 has a positive charge and particle 2 has a negative charge.

b.
Both particles are positively charged.

c.
Both particles are negatively charged.

d.
Particle one has a negative charge and particle 2 has a positive charge.

e.
The direction of the paths depends on the magnitude of the velocity, not on the sign of the charge.

Physics & Space Science