Author Question: An electron is trapped in a quantum well that is 48.6 nm wide. Calculate the minimum uncertainty ... (Read 89 times)

itsmyluck · **on:** Jul 29, 2018

An electron is trapped in a quantum well that is 48.6 nm wide.

Calculate the minimum uncertainty in its velocity. (h = 6.626 10-34 J s, melectron = 9.11 10-31 kg)
A) 2.38 103 m/s
B) 1.01 103 m/s
C) 3.34 104 m/s
D) 1.79 104 m/s
E) 7.49 103 m/s

Question 2

A giant star in another galaxy exploded 67 million years ago, forming a supernova. The event is observed by an astronomer on Earth.

Estimate the speed at which the supernova (and its galaxy) recedes from Earth if the Hubble constant is 22 km/s per million light-years. (c = 3.00 108 m/s, 1 ly = 9.461 1015 m, 1 y = 3.156 107 s)
A) 4700 km/s B) 2700 km/s C) 1500 km/s D) 1200 km/s E) 670 km/s