1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Digiron [165]
2 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]2 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

You might be interested in
A car has a kinetic energy of 5.32*10^5 j when traveling at a speed of 20 m/s what is its mass
Maslowich

Answer: Mass of car is 2660kg

Explanation:

Use equation for Kinetic ene)rgy :

Ek=(m*V²)/2

from this eqation you can get mass

m*V²=Ek*2

m=Ek*2/v²

Ek=5.32*100000J

V=20m/s

m=?

m=2*5.32*100000J/(20m/s)²

m=2660kg or 2.66t

4 0
2 years ago
Use the law of conservation of energy (assume no friction nor air resistance) to determine the kinetic and potential energy at t
slava [35]

Answer:

Part A

1) At the starting point, we have;

PE = 40,000 J

2) PE = 0 J, KE = 40,000 J

3) KE = 20,000 J

4) PE = 15,000 J

5) KE = 32,500 J

6) KE = 40,000 J, PE = 0 J

7) KE = 35,000 J

8) KE = 40,000 J, PE = 0 J

Part B

The total Mechanical Energy = ME = 40,000 J

At the final point, we have;

ME = KE + PE = 40,000 J + 0 J = 40,000 J

Explanation:

Part A

By the law of conservation of energy, we have;

ME = PE + KE

Where;

ME = The total Mechanical Energy of the system

PE = The Potential Energy of the system

KE = The Kinetic Energy of the system

Where there is no friction, we have;

At the final stage, KE = 40,000 J. PE = 0 J

Therefore, ME = PE + KE = 40,000 J + 0 J = 40,000 J

1) At the starting point, we have;

KE = 0 J, therefore, PE = ME - KE = 40,000 J - 0 J = 40,000 J

2) At the bottom of the roller coaster, at the same level the PE is taken as PE = 0 J at the final stage, we have;

PE = 0 J, therefore, KE = ME - PE = 40,000 J - 0 J = 40,000 J

3) Where PE = 20,000 J, KE = ME - PE = 40,000 J - 20,000 J = 20,000 J

4) Where KE = 25,000 J, PE = ME - KE = 40,000 J - 25,000 J = 15,000 J

5) Where PE = 7,500 J, KE = ME - PE = 40,000 J - 7,500 J = 32,500 J

6) At the bottom KE = 40,000 J, PE = 0 J

7) Where PE = 5,000 J, KE = ME - PE = 40,000 J - 5,000 J = 35,000 J

8) KE = 40,000 J, PE = 0 J

Part B

The given that there is no friction nor air resistance, the total Mechanical Energy, ME, is constant and equal to the sum of the Potential Energy, PE and the Kinetic Energy, KE, as follows;

ME = KE + PE

At the final point, we have;

ME = 40,000 J + 0 J = 40,000 J

The total Mechanical Energy = ME = 40,000 J

8 0
1 year ago
I NEED ANSWERS ASAP! IM GIVING 100 POINTS!
Akimi4 [234]

Answer:

1.b 2.d 3.b 4.a 5.c

Explanation:

I tried my very best and I hoped these helped

6 0
1 year ago
Read 2 more answers
Is the author of the article suggesting that we will be able to maintain CO2 levels in the future? Which selection from the arti
Luba_88 [7]

Answer:

This is your choice. If you choose yes choose A. For 2 choose C.

Explanation:

7 0
2 years ago
Read 2 more answers
a 2-kg object is dropped from a height of 1000 m. What is the force of air resistance on the object when it reaches terminal vel
strojnjashka [21]
It stops accelerating when the air resistance is equal to its weight.
That's (m•g)

= (2 kg) • (9.8 m/s^2)

= 19.6 newtons
5 0
2 years ago
Other questions:
  • Train cars are coupled together by being bumped into one another. Suppose two loaded train cars are moving toward one another, t
    7·1 answer
  • Moving water, like that of a river, carries sediment as it moves along its bed. The faster the water flows, the more sediment th
    8·1 answer
  • What happens in this circuit if one of the light bulbs is unscrewed?
    15·2 answers
  • A bicycle tire has a pressure of 6.9 × 105 Pa at a temperature of 17.5°C and contains 2.00 L of gas. show answer Incorrect Answe
    6·1 answer
  • George walls to a friend’s house. He walks 750 meters north, then realizes he walked too far. He turns around and walks 250 mete
    12·1 answer
  • An object has a. Kinetic energy of 17j and a mass of 27 kg, how fast is the object moving?
    14·1 answer
  • What exercise will strengthen your legs?
    5·1 answer
  • An object weighs 30 N on Earth. A second object weighs 30 N on the Moon. Which has the greater mass?
    12·1 answer
  • If a 2 kg ball is traveling at 4 meters per second, what is its kinetic energy?
    15·2 answers
  • A bat emitts a sonar sound wave (343 m/s) that bounces off a mosquito 8.42 m away
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!