Aluminium has atomic number 13 . In its ground state, how many electrons are in its n = 1 shell?

a. 6
b. 2
c. 3
d. 10
e. 16

b

Physics & Space Science

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A long straight wire (diameter = 2.0 mm) carries a current of 30 A. What is the magnitude of the magnetic field 2.5 mm from the axis of the wire?

a. 3.2 mT b. 2.8 mT c. 2.4 mT d. 3.6 mT e. 3.0 mT

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One of the harmonics of a column of air open at one end and closed at the other has a frequency of 448 Hz and the next higher harmonic has a frequency of 576 Hz. How long is the air column? The speed of sound in air is 343 m/s

A) 1.34 m B) 0.670 m C) 0.335 m D) 1.00 m E) 2.68 m

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A small sphere of initial volume V is filled with n moles of helium at initial pressure and temperature P and T. Which of the following statements is true?

n/2 moles of gas are removed, the volume is decreased to V/2, and the pressure decreases to P/4 with a drop in temperature of T/2

The volume decreases to V/2, and the pressure increases to 4P when the temperature is T/2 n moles of gas are added, the total sample is heated to 2T, and the pressure drops to P/2 when the volume increases to 8V The amount of gas is doubled to 2n, the pressure is doubled to 2P, and the volume is doubled to 2V, with a corresponding temperature drop to T/2

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Physics & Space Science

What is the most abundant molecule in interstellar clouds besides molecular hydrogen?

A) ammonia B) water C) methane D) molecular helium E) carbon monoxide

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Physics & Space Science