If We Start With 400 Atoms of a Radioactive Substance, How Many Would Remain After One Half-life ?

Answers

Answer 1

Answer: If it's half life, that means that half of the atoms have died out. Therefore, 200 atoms have died, so there are 200 atoms left (exactly one half of 400)

Answer 2

Answer: 200, the half life of a radioactive substance is pretty simple to remember. It is literally cutting it in half, however, don't make the same mistake I did in this subject, the second half life does not reduce it to 0, it reduces it to 100. It just keeps half-lifing over and over again. For example: 400 atoms after one half life:200, after two: 100, after 3, 50, and so on.

Related Questions

Suppose your rub a balloon in your hair and it acquires a static charge of −2 × 10⁻⁹c. what is the magnitude of the electric field created by the balloon at a location 1 m due north of the balloon? Coulomb’s constant is 9 × 10⁹ N · m²/c² . Answer in units of N/C
Which of the following are pure substances?a. solutions b. compounds c. homogeneous mixtures d. colloids
List 3 examples behaviors of solid and the 3nwrgy associated with them
Describe two of Tesla's inventions that influencedtechnology and are still in use today.
A 3,000-N force gives an object an acceleration of 15 m/s2. The mass of the object is

If you apply 100.0 N of force to lift an object with a single, fixed pulley, then what is the resistive force?

Answers

If you apply 100.0 N of force to lift an object with a single, fixed pulley, then the resistive force is also equivalent to 100 Newtons of force. Since the weight of the object was not mentioned, it is assumed that it has already been taken into account in the 100 N value of force. This follows Newton's law of motion of equal action and reaction.

as you are leaving a building, the door opens outward. if the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

Answers

The correct answer for the question that is being presented above is this one: "B) down." As you are leaving a building, the door opens outward. if the hinges on the door are on your right, the angular velocity of thedoor as you open it us 'down.'

Here are the following choices:
A) up
B) down
C) to your left
D) to your right

In 1911, Ernest Rutherford and his assistants Geiger and Marsden conducted an experiment in which they scattered alpha particles (nuclei of helium atoms) from thin sheets of gold. An alpha particle, having charge 2e and mass 6.64 10-27 kg, is a product of certain radioactive decays. The results of the experiment led Rutherford to the idea that most of an atom's mass is in a very small nucleus, with electrons in orbit around it. Assume an alpha particle, initially very far from a stationary gold nucleus, is fired with a velocity of 1.50 107 m/s directly toward the nucleus (charge 79e). What is the smallest distance between the alpha particle and the nucleus before the alpha particle reverses direction?

Answers

Answer:

Explanation:

We shall apply conservation of mechanical energy

kinetic energy of alpha particle is converted into electric potential energy.

1/2 mv² = k q₁q₂/d , d is closest distance

d = 2kq₁q₂ / mv²

= 2 x 9 x 10⁹ x 79e x 2e / 4mv²

= 1422 x2x (1.6 x 10⁻¹⁹)² x 10⁹ /4x 1.67 x 10⁻²⁷ x (1.5 x 10⁷)²

= 3640.32 x 10⁻²⁹ /2x 3.7575 x 10⁻¹³

= 484.4 x 10⁻¹⁶

=48.4 x 10⁻¹⁵ m

Which one of the following sources produces the highest energy photons? A)a doctor's x-ray source B)a heat lamp in a restaurant C)a microwave oven D) gamma rays from a star radio E)waves from a local station

Answers

Answer:D) Gamma rays

Explanation:

Energy of a photon= h( Planck constant) * f (frequency)

So we take a look at the electromagnetic spectrum i am attaching and see which wave will have the highest frequency.

As a note frequency is inversely proportional to wavelength so highest energy is also shortest wavelength.

Therefore the highest energy are gamma rays

Hope this helps

Final answer:

Among the options provided, gamma rays from a star radio produce the highest energy photons. This is due to the larger energy differences in gamma rays. The radiation emitted by a microwave oven, a heat lamp, local station waves, or a doctor's X-ray are of lesser energy comparatively.

Explanation:

The source that produces the highest energy photons among the options provided is 'gamma rays from a star radio'. This is because gamma rays are part of the electromagnetic spectrum and known for having short wavelengths and high energy. In fact, the energy of gamma rays is much larger than the energy released by a microwave oven, a heat lamp, radio waves from a local station or even a doctor's X-ray machine.

Nuclear energy shells in gamma rays have energy differences that are millions of times larger than electromagnetic radiation from electronic transitions. In contrast, examples like a microwave oven work with much smaller energy scales, producing electromagnetic radiation that is absorbed by water molecules, leading to an increase in the molecules' rotational energies.

Microwaves and heat lamps emit infrared radiation, doctors use X-rays, and local stations emit radio waves. However, none of these have as much energy as gamma rays, which can be produced in stars, among other places. Gamma rays are the most energetic form of light and are created by the hottest and most energetic objects in the universe, such as stars and black holes.

Learn more about Gamma Rays here:

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A 360-N child is in a swing that is attached to a pair of ropes 1.90 m long. Find the gravitational potential energy of the child–Earth system relative to the child's lowest position at the following times.

Answers

Answer:

684J

Explanation:

So basically the formula for gravitational potential energy is Mass X Gravity X height. That is G.p.e = mgh

We don't have the mass but since we have the height, we multiply directly with the height since the quantity of weight is already given.

so G.p.e = 360 X 1.9 = 684J

Note that; The answer is in joules because g.p.e is work done.

Hope that was helpful!!

Calculate the wavelength of a radio wave whose frequency is 900 kHz. (v = 3.00 · 108 m/s.)

Answers

The wavelength of a radio wave whose frequency is 900 kHz will be 10³/3, or you can write it as 333.33 meters.

What is Wavelength?

To characterize waveform signals that are transmitted across wires or into space, the term "wavelength" is used to refer to the separation between two identical positions (adjacent crests) in succeeding cycles. Typically, this length in wireless systems is measured in meters (m), centimeters (cm), or millimeters (mm) (mm). When describing the wavelength of infrared (IR), visible light (UV), and gamma radiation, units of 10⁻⁹ nanometers (nm) or angstroms (10-10 m) are more usually used.

Frequency, which is defined as the number of wave cycles per second, and wavelength have an inverse relationship. The wavelength of a signal decreases with increasing frequency, or we can say that wavelength and refractive index are inversely proportional to each other.

According to the question, the given values are :

v = 3 × 10⁸ m/s and,

frequency, f = 900 kHz or,

f = 900 × 10³ Hz

λ = v / f

λ = (3 × 10⁸) / (3 × 10³)

λ = 10³/3 metes or,

λ = 333.33 meters.

So, the wavelength of a radio wave is 333.33 meters.

To get more information about wavelength :

brainly.com/question/13533093

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