Which process produces the energy radiated by the star when it becomes a main sequence star?

You are given a material which produces no initial magnetic field when in free space. When it is placed in a region of uniform m

seropon [69]

Answer:

This material exhibits paramagnetism.

Explanation:

A paramagnetic material has these features: It doesn’t have any magnetic properties when placed in an external magnetic field, it gains and then loses the magnetic property as the external field is removed.

Such materials have magnetic moments oriented in random directions, thus making the net magnetic moment, zero. But when placed in an external field, they do possess a net magnetic moment. When the magnetic field is removed, they lose the magnetic property.

Thus, the material which produces no initial magnetic field when placed in a uniform magnetic field produces an additional internal magnetic field parallel to the original field. Also, it loses the magnetic properties as soon as the external magnetic field is removed. Then, the magnetism the material exhibits is paramagnetic.

7 0

3 years ago

A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from t

marishachu [46]

Answer:

The impact occured at a distance of 2478.585 meters from the person.

Explanation:

(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:

<em>A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)</em>

Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete ( $\Delta t$ ), in seconds:

$\Delta t = t_{A}-t_{C}$ (1)

Where:

$t_{C}$ - Time spent by the sound in concrete, in seconds.

$t_{A}$ - Time spent by the sound in the air, in seconds.

By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:

$\Delta t = \frac{x}{v_{A}}-\frac{x}{v_{C}}$

$\Delta t = x\cdot \left(\frac{1}{v_{A}}-\frac{1}{v_{C}} \right)$

$x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }$ (2)

Where:

$v_{C}$ - Speed of the sound in concrete, in meters per second.

$v_{A}$ - Speed of the sound in the air, in meters per second.

$x$ - Distance traveled by the sound, in meters.

If we know that $\Delta t = 6.4\,s$ , $v_{C} = 3000\,\frac{m}{s}$ and $v_{A} = 343\,\frac{m}{s}$ , then the distance travelled by the sound is:

$x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }$

$x = 2478.585\,m$

The impact occured at a distance of 2478.585 meters from the person.

7 0

3 years ago

Two loudspeakers emit sound waves along the x-axis. The sound has maximum intensity when the speakers are 19 cm apart. The sound

Vanyuwa [196]

Answer:

Explanation:

The former is the case of constructive interference and the later case relates to destructive interference.

For listener, path difference is the separation of loudspeaker as listener is not standing in between the speaker.

If λ be the wave length

For constructive interference

19 = n λ

For destructive interference

29 = (2n+1) λ / 2

= n λ + λ / 2

= 19 + λ / 2

10 = λ / 2

λ = 20 cm

= 0. 20 m

7 0

3 years ago

The index of refraction for red light in a certain liquid is 1.303; the index of refraction for violet light in the same liquid

kotegsom [21]

Snell's law states: n1/n2 = Sin Ф2/Sin Ф1

But n2/n1 = 1.303 and 1.326 for red light and violet light respectively (for this case) and Ф1 = 45

Therefore,
Фr = Sin ^-1{1/1.303 *Sin 45} = 32.87°
Фv = Sin ^-1 {1/1.326* Sin 45} = 32.23°

Then,
Dispersion, Фv - Фr = 32.23 - 32.87 = -0.64°

3 0

4 years ago

A 0.100 kg ball hangs from a spring of negligible mass. When the ball is hung on the spring and is at rest, the spring is stretc

anzhelika [568]

Answer:

a) 4.9 N/m

b) 1.4 m/s

c) 0.225 s

Explanation:

Hooke's law states that

F = k * Δx

Where

F: force applied to a spring

k: constant of the spring

Δx: elongation of the spring

The force applied in this case is the weight of the ball, this is

P = m * g = 0.1 kg * 9.81 m/s^2 = 0.981 N

Rearrainging Hooke's law:

k = F / Δx

k = 0.981 / 0.2 = 4.9 N/m

If the ball is pulled down the spring will acquire some potential energy, when it is released, the potential energy will be released as kinetic energy on the ball

$Ec = \frac{1}{2} * m * v^2$

Elastic potential energy is:

$U = \frac{1}{2} * k * \Delta x^2$

The energy gained from the 0.2m pull will be turned into kinetic energy

Ec = U

Therefore:

$\frac{1}{2} * m * v^2 = \frac{1}{2} * k * \Delta x^2$

Rearranging:

$v^2 = \frac{k}{m} * \Delta x^2$

$v = \Delta x * \sqrt{\frac{k}{m}}$

$v = 0.2 * \sqrt{\frac{4.9}{0.1}} = 1.4 m/s$

After being released the ball will oscillate at the natural frequency of the system, which is

$f = \frac{1}{2 * \pi} * \sqrt{\frac{k}{m}}$

And the period will be:

$T = 2 * \pi * \sqrt{\frac{m}{k}}$

The period in this case is:

$T = 2 * \pi * \sqrt{\frac{0.1}{4.9}} = 0.9 s$

The ball will move up and down taking T time to complete a cycle, the movement from the stretched position to the equilibrium position takes T/4 = 0.225 s

8 0

3 years ago