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3 years ago

1 gram of radium is reduced by 3.1 mg in 5 years by alpha decay.

Physics

1 answer:

Whitepunk [10]3 years ago

4 0

Answer:

1 gm = 1000 mg

N = No e^-y t where y = lambda the decay constant

N / N0 = .9969

ln .9969 = - y t

-.00310 = - 5 y

y = .00310 / 5 = .000621

So the half-life = .693 / y

T^1/2 = .693 / .000621 = 1116 or about 1120 yrs

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Setler [38]

When sphere A and B are brought in contact and separated, charge on each sphere becomes [2x10^-6 + (-4x10^-6)]/ 2 = -1x10^-6 C.

That is, charge is equally separated and is the average of charges on both spheres. The reason behind equal charge on both spheres after separation is, when they are kept in contact, their potential difference becomes same.

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3 years ago

3. The car's mass is 400 kg. It moves at a velocity of 20 m/s. Calculate the car's momentum. *

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3 years ago

Given that ethylene has a λmax of 175nm, butadiene has a λmax of 220nm, and 2-methyl-1,3-butadiene has a λmax or 215nm, what is

Vika [28.1K]

The λmax of 2,3,4-trimethylhexatriene is 280 nm.

Ethylene has a λmax of 175nm.

Butadiene has a λmax of 220nm.

2-methyl-1,3-butadiene has a λmax or 215nm.

1,3,5-hexatriene has a λmax of 258nm.

Woodward's rules, sometimes known as Woodward-Fieser rules (after Louis Fieser) and named after Robert Burns Woodward, are a number of sets of empirically developed principles that aim to forecast the wavelength of the absorption maximum (max) in an ultraviolet-visible spectrum of a certain molecule.

By using the Woodward Fieser rule,

R- (Alkyl Group) .... +5 nm = 5 × 2 = 10

RO- (Alkoxy Group) .. +6 = 6 × 2 = 12

Adding 22nm to the λmax of 1,3,5-hexatriene as it has 2 alkyl groups and 2 alkoxy groups to form 2,3,4-trimethylhexatriene.

The λmax of 2,3,4-trimethylhexatriene is 280 nm.

Learn more about Woodward-Fieser here:

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2 years ago

As light travels from air to water to glass, it will refract. The best explanation for this would be

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D) The speed of a wave slows as it travels at different speed in different media.

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3 years ago

Read 2 more answers

(a) what will an object weigh on the moon's surface if it weighs 100 n on earth's surface

juin [17]

We know the equation

weight = mass × gravity

To work out the weight on the moon, we will need its mass, and the gravitational field strength of the moon.
Remember that your weight can change, but mass stays constant.

So using the information given about the earth weight, we can find the mass by substituting 100N for weight, and we know the gravity on earth is 10Nm*2 (Use the gravitational field strength provided by your school, I am assuming yours in 10Nm*2)

Therefore,

100N = mass × 10
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Now, all we need are the moon's gravitational field strength and to apply this to the equation

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3 years ago