To start this question, we should know what is the atomic number of cobalt. The atomic number (the number of protons) of Cobalt is Z =27.
Now, we know that a Cobalt 60 isotope means an isotope of Cobalt whose Atomic Mass is 60.
Thus, in a Cobalt 60 isotope, the number of neutrons in the nucleus are
From the question we know that the given nuclear mass is 59.933820 u.
Now, the mass defect of Cobalt 60 can be easily calculated by adding the masses of the protons and the neutrons as per our calculations and subtracting the given nuclear mass from it.
Thus,
Mass Defect = (Number of Protons Mass of Proton given in the question) + (Number of Neutrons Mass of Neutron given in the question)-59.933820 u
Thus, the required Mass Defect is 0.5634u.
In eV, the Mass Defect is 
Three that are equivalent are 12:9 8:6 28:21
Answer:
(i) ∠ABH = 14.5°
(ii) The length of AH = 4.6 m
Step-by-step explanation:
To solve the problem, we will follow the steps below;
(i)Finding ∠ABH
first lets find <HBC
<BHC + <HBC + <BCH = 180° (Sum of interior angle in a polygon)
46° + <HBC + 90 = 180°
<HBC+ 136° = 180°
subtract 136 from both-side of the equation
<HBC+ 136° - 136° = 180° -136°
<HBC = 44°
lets find <ABC
To do that, we need to first find <BAC
Using the sine rule
= 
A = ?
a=6.9
C=90
c=13.2
= 
sin A = 6.9 sin 90 /13.2
sinA = 0.522727
A = sin⁻¹ ( 0.522727)
A ≈ 31.5 °
<BAC = 31.5°
<BAC + <ABC + <BCA = 180° (sum of interior angle of a triangle)
31.5° +<ABC + 90° = 180°
<ABC + 121.5° = 180°
subtract 121.5° from both-side of the equation
<ABC + 121.5° - 121.5° = 180° - 121.5°
<ABC = 58.5°
<ABH = <ABC - <HBC
=58.5° - 44°
=14.5°
∠ABH = 14.5°
(ii) Finding the length of AH
To find length AH, we need to first find ∠AHB
<AHB + <BHC = 180° ( angle on a straight line)
<AHB + 46° = 180°
subtract 46° from both-side of the equation
<AHB + 46°- 46° = 180° - 46°
<AHB = 134°
Using sine rule,
= 
AH = 13.2 sin 14.5 / sin 134
AH≈4.6 m
length AH = 4.6 m
5/6 = .83333333333333333333333333.... It goes on...
.833333333333333333 * 18 = 15
15 is your answer
Another way you could do it is 18/6 = 3
3+3+3+3+3 = 15
3 being 1/6th of 18 *Hope This Helps...*
Answer: The value of y=9.
