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Digiron [165]
3 years ago
8

Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to incandescence for long peri

ods of time. Natural thorium is almost 100% 232Th, with a half-life of 1.405 ✕ 1010 y. If an average lantern mantle contains 200 mg of thorium, what is its activity (in Bq)?
Physics
1 answer:
maksim [4K]3 years ago
5 0

Answer:

The activity is 811.77 Bq

Solution:

As per the question:

Half life of Thorium, t_{\frac{1}{2}} = 1.405\times 10^{10}\ yrs

Mass of Thorium, m = 200 mg = 0.2 g

M = 232 g/mol

Now,

No. of nuclei of Thorium in 200 mg of Thorium:

N = \frac{N_{o}m}{M}

where

N_{o } = Avagadro's number

Thus

N = \frac{6.02\times 10^{23}\times 0.2}{232} = 5.19\times 10^{20}

Also,

Activity is given by:

\frac{0.693}{t_{\frac{1}{2}}}\times N

A= \frac{0.693}{1.405\times 10^{10}}\times 5.19\times 10^{20} = 2.56\times 10^{10}\ \yr

A = \frac{2.56\times 10^{10}}{365\times 24\times 60\times 60} = 811.77\ Bq

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3 years ago
What is the lowest mass that an object can have and still be a star?
CaHeK987 [17]

Answer:

The lowest mass that an object can have to be considered a star is 0.08 solar masses.    

Explanation:

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5 0
4 years ago
The two forces acting on a boat or some other floating object _______are and gravity​
lubasha [3.4K]

Answer:

The two forces acting on a boat or some other floating object are buoyancy and gravity

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A trough is 3 meters long, 2 meters wide, and 4 meters deep. The vertical cross-section of the trough parallel to an end is shap
irina1246 [14]

Answer:

work done is 470400 J

Explanation:

given data

long = 3 m

wide = 2 m

deep = 4 m

density = 1000 kg/m³

to find out

Find the amount of work in joules

solution

we know here volume = area ×  length

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area = 4 m²

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weight = 117600 N

so

work done = weight × height

work done = 117600× 4

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