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3 years ago

The cells lie odjacent to the sieve tubes

Physics

1 answer:

nignag [31]3 years ago

4 0

Answer:

<h2>Almost always adjacent to nucleus containing companion cells, which have been produced as sister cells with the sieve elements from the same mother cell. </h2>

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How many grams of CO-60 result in 1 Millicuire of activity? How many years until the activity decays to 1 microcuire tl/2 =5.3 Y

vredina [299]

Answer:

m =8.81*10^{-6}grams

time t = 52.8 year

Explanation:

GIVEN DATA:

the half life of the CO-60 is, T_1/2 = 5.27 years = 1.663 e+8 s

activity dN/dt = 1 mCi = 3.7 X 10^7 decay/s

activity , $dN/dt = N* \lambda$

$\frac{dN}{dt} = N* \frac{ln2}{T_1/2}$

$N = \frac{(dN/dt )(T1/2)}{ln2}$

= ( 3.7 X 10^7 )(1.663*10^8 ) / ln2

= 8.877*10^{16}

Number of moles:

n = N/NA = 8.877*10^{16} / 6.022X10^23 = 1.474*10^{-7} mol

mass of the CO-60 is,

m = n*M = [1.474*10^{-7} mol]*[59.93 grams /mol] = 8.81*10^{-6}grams

-----------------------------------------------------------------------------------------

time t = -[T1/2 / ln2]*ln[N/N0]

= - [5.3 years / ln2]*ln[1x10-6/1x10-3]

= 52.8 year

8 0

4 years ago

The toy car is about 3 inches long is an example of a ?

balandron [24]

Answer:

a quantitative observation because it includes numerical data

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3 years ago

A charge q = 3 × 10-6 C of mass m = 2 × 10-6 kg, and speed v = 5 × 106 m/s enters a uniform magnetic field. The mass experiences

NeX [460]

Answer:

Magnetic field, B = 0.004 mT

Explanation:

It is given that,

Charge, $q=3\times 10^{-6}\ C$

Mass of charge particle, $m=2\times 10^{-6}\ C$

Speed, $v=5\times 10^{6}\ m/s$

Acceleration, $a=3\times 10^{4}\ m/s^2$

We need to find the minimum magnetic field that would produce such an acceleration. So,

$ma=qvB\ sin\theta$

For minimum magnetic field,

$ma=qvB$

$B=\dfrac{ma}{qv}$

$B=\dfrac{2\times 10^{-6}\ C\times 3\times 10^{4}\ m/s^2}{3\times 10^{-6}\ C\times 5\times 10^{6}\ m/s}$

B = 0.004 T

B = 4 mT

So, the magnetic field produce such an acceleration at 4 mT. Hence, this is the required solution.

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3 years ago

The low-pressure area near Earth’s equator is filled by cool air moving in from ________. Btw this is science

bonufazy [111]

Answer:

the north and south pole

Explanation:

this should be the correct answer

5 0

2 years ago

Determine the weight of an average physical science textbook whose mass is 3.1 kilograms. The acceleration due to gravity is 9.8

zvonat [6]

Weight equals mass*gravity
W = mg

Given m = 3.1 kg, g = 9.8 m/s^2

W = (3.1)(9.8)
W = 30.38

6 0

3 years ago

The cells lie odjacent to the sieve tubes​

The cells lie odjacent to the sieve tubes