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3 years ago

Describe some tests that could be done to determine what an unknown substance is.

Physics

2 answers:

valentina_108 [34]3 years ago

6 0

Answer:

Simple chemical tests can be used to identify the presence of various elements or classes of molecules (Tollen's test). ... Electron spin resonance (ESR): Also referred to as electron paramagnetic resonance (EPR), this method uses the spins of unpaired electrons in molecules to determine structure

natima [27]3 years ago

3 0

Answer:

by finding melting and boiling points

Explanation:

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An LED with total power P tot = 960 mW emits UV light of wavelength 360 nm. Assuming the LED is 55% efficient and acts as an iso

Anit [1.1K]

Answer:

$E_0=225.09N/C$

Explanation:

We are given that

Power,Ptot=960mW= $960\times 10^{-3}W$

$1mW=10^{-3} W$

Wavelength, $\lambda=360 nm=360\times 10^{-9} m$

$1nm=10^{-9} m$

Distance,r=2.5 cm= $2.5\times 10^{-2} m$

1m=100 cm

Efficiency=55%

Power radiation emitted= $\frac{55}{100}\times 960\times 10^{-3}=0.528W$

Intensity,I= $\frac{P}{4\pi r^2}$

$I=\frac{0.528}{4\pi(2.5\times 10^{-2})^2}=67.26W/m^2$

Intensity, $I=\frac{1}{2}c\epsilon_0E^2_0$

$E^2_0=\frac{2I}{c\epsilon_0}$

Where $\epsilon_0=8.85\times 10^{-12}$

$c=3\times 10^8 m/s$

$E_0=\sqrt{\frac{2I}{c\epsilon_0}}$

$E_0=\sqrt{\frac{2\times 67.26}{3\times 10^8\times 8.85\times 10^{-12}}}$

$E_0=225.09N/C$

4 0

3 years ago

HELP ASAP!! WILL TRY TO GIVE BRAINLIEST

Verdich [7]

Answer:

Diffusion is the movement of a molecule from an area where the molecule is in high concentration to an area where the molecule is in low concentration. Facilitated diffusion is the movement of a molecule from an area of high concentration to an area where the molecule is in low concentration. Osmosis is the diffusion (high to low concentration) of water through a semi-permeable membrane. Water moves from an area of high water molecule concentration (and lower solute concentration) to an area of low concentration (and higher solute concentration.

Hope this Helps!!!

7 0

3 years ago

A 20-cm-long stick of m = 0.600 kg is lifted by a rope tied 5.0 cm from the upper end. The other end touches a smooth floor. The

Liula [17]

Answer:

https://www.chegg.com/homework-help/questions-and-answers/part-20-cm-long-stick-m-0400-kg-lifted-rope-tied-70-cm-upper-end-end-touches-smooth-floor--q81268572

3 0

2 years ago

A 56.0kg ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.50 turns each

Arada [10]

Answer:

Net force = 129.4, Force as multiple of weight of her hand = 18.84

Explanation:

Given Data:

Total body weight = 56.0 kg ;

no. of turns = 2.5/second ;

hand to hand distance = 1.5m ;

weight of hand = 1.25% of body weight ;

Solution:

mass of hand = $\frac{1.25}{100}$ *56 = 0.7kg ;

radius = d/2 = 1.5/2 = 0.75m ;

Now we need to find velocity, as we know that velocity can be calculated by dividing distance by time

v = d/t = $\frac{2.5*2*3.14*0.75}{1}$ = 11.775 m/s or 12 m/s;

The formula to calculate force is given as

F = mv²/r = (0.7*11.775²)/0.75 = 129.4 N

To calculate force as multiple of weight on her hand, we need to calculate the gravitational force W on her hand first.

W = gm = 9.81 * 0.7 = 6.867 N

Now the wieght on her hand can be represented by

$\frac{Force_{net} }{weight of hand}$ = 129.4 / 6.867 = 18.84

3 0

4 years ago

What is the great egg drop experiment about?

kondaur [170]

Whichever person or group can build something to protect the egg from cracking when it is dropped from a high spot without it breaking or cracking wins

6 0

3 years ago

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