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3 years ago

Heat transfer that doesn’t need a medium? A) Radiation B)Convection C)Conduction

2 answers:

8 0

Radiation is a method of heat transfer through electromagnetic waves. This transfer does not require a medium in order for heat to be transferred.

The solution is A.

Rufina [12.5K]3 years ago

6 0

The correct answer is A

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1 Calculate the size of the quantum involved in the excitation of (a) an electronic motion of frequency 1.0 × 1015 Hz, (b) a mol

torisob [31]

Answer: a) E= 6.63x10^-19J

E= 3.97×10^2KJ/mol

b) E = 3.31×10^-19J

E= 18.8×10^4 KJ/mol

C) E = 1.32×10^-33J

E= 8.01×10^-10KJ/mol

Explanation:

a) E = h ×f

h= planks constant= 6.626×10^-34

E=(6.626×10^-34)×(1.0×10^15)

E=6.63×10^-19J

1mole =6.02×10^23

E=( 6.63×10^-19)×(6.02×10^23)

E=3.97×10^2KJ/mol

b) E =(6.626×10^-34)/(1.0×10^15)

E=3.13×10^-19J

E= 3.13×10^-19) ×(6.02×10^23)

E= 18.8×10^3KJ/MOL

c) E= (6.626×10^-34) /0.5

E= 1.33×10^-33J

E= (1.33×10^-33) ×(6.02×10^23)

E= 8.01×10^-10KJ/mol

8 0

2 years ago

Start from 0 m/s and accelerate at 2m/s? Calculate the speed in m/s after acceleration for 5 seconds.

valentinak56 [21]

Answer:

10m/s

Explanation:

2m/s x 5s=10m/s

4 0

2 years ago

3.1 Two waves A and B have frequencies 256 Hz and 1024 Hz respectively have amplitude in ratio 3:1 1.What is their ratio of freq

scoundrel [369]

Answer:

1. the one with the raito

2. the one that stubbed their toe

Explanation:

8 0

2 years ago

Engineers and science fiction writers have proposed designing space stations in the shape of a rotating wheel or ring, which wou

Gennadij [26K]

Answer:

a. The station is rotating at $1.496 \frac{rev}{min}$

b. the rotation needed is $2.8502 \frac{rev}{min}$

Explanation:

We know that the centripetal acceleration is

$a_{c}= \omega ^2 r$

where $\omega$ is the rotational speed and r is the radius. As the centripetal acceleration is feel like an centrifugal acceleration in the rotating frame of reference (be careful, as the rotating frame of reference is <u>NOT INERTIAL,</u> the centrifugal force is a fictitious force, the real force is the centripetal).

The rotational speed is :

$2.7 \frac{m}{s^2} = \omega ^2 * 110 \ m$

$\omega ^2 = \frac{2.7 \frac{m}{s^2}} {110 \ m}$

$\omega = \sqrt{ 0.02454 \frac{rad^2}{s^2} }$

$\omega = 0.1567 \frac{rad}{s}$

Knowing that there are $2\pi \ rad$ in a revolution and 60 seconds in a minute.

$\omega = 0.1567 \frac{rad}{s} \frac{1 \ rev}{2\pi \ rad} \frac{60 \ s}{1 \ min}$

$\omega = 1.496 \frac{rev}{min}$

The rotational speed needed is :

$9.8 \frac{m}{s^2} = \omega ^2 * 110 \ m$

$\omega ^2 = \frac{9.8 \frac{m}{s^2}} {110 \ m}$

$\omega = \sqrt{ 0.08909 \frac{rad^2}{s^2} }$

$\omega = 0.2985 \frac{rad}{s}$

Knowing that there are $2\pi \ rad$ in a revolution and 60 seconds in a minute.

$\omega = 0.2985 \frac{rev}{min} \frac{1 \ rev}{2\pi \ rad} \frac{60 \ s}{1 \ min}$

$\omega = 2.8502 \frac{rev}{min}$

3 0

2 years ago

Read 2 more answers

On the day Harvey is to present his dissertation, he wakes up with a severe headache. During the presentation, he feels no pain

luda_lava [24]

Gate-control theory

<h3>What is Gate-control theory?</h3>

According to the Gate Control Theory of Pain, the spinal cord has a system that allows pain signals to be amplified in the brain before being processed at the spinal cord itself, or attenuated there.

The mechanism that allows or prevents the passage of pain signals is known as the gate. The gate may be open or it may be closed, one of two possibilities:

When the gate is open, pain signals can enter and are delivered to the brain, where they are perceived as pain.
If the gate is closed, pain signals will be prevented from ascending to the brain and won't be felt.

The administration of a non-noxious (soothing or light rubbing) stimulus can help engage the gate control mechanism and alleviate pain in those who are exposed to painful (noxious) stimuli.

Learn more about gate-control theory here:

brainly.com/question/15561467

#SPJ4

8 0

11 months ago