Answer:
67
Explanation:
- The atomic number (Z) of an atom is equal to the number of protons in the nucleus
- The mass number (A) of an atom is equal to the sum of protons and neutrons in the nucleus
Therefore, calling p the number of protons and n the number of neutrons, for element X we have:
Z = p = 23
A = p + n = 90
Substituting p=23 into the second equation, we find the number of neutrons:
n = 90 - p = 90 - 23 = 67
Answer: Try C
Explanation:
It's the only one that makes since.
A because it's the smaller the thicker you just can't have 0 gage
Answer:
The time is 106.7 minute.
Explanation:
Given that,
Density 
Current 
Diameter of wire = 1.2 mm
Length = 31 cm
We need to calculate the drift velocity
Using formula of drift velocity


Put the value into the formula


We need to calculate the time
Using formula for time


Where, l = length
= drift velocity
Put the value into the formula



Hence, The time is 106.7 minute.
From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is

Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,

Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm