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3 years ago

Pls help I will mark

Physics

1 answer:

Paraphin [41]3 years ago

3 0

Metals contain the most and semiconductors contain the least amount. Hope this helps.

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List three signs that could make you think that a chemical reaction was taking place.

algol13

1. Release of gases
2. Bubbling
3. And change in color- this one can also be for a physical change.

Hope this helps.

5 0

3 years ago

Two electrons are initially at rest separated by a distance of 2nm. At time t=0, they start to move apart due to Coulombic repul

Gnom [1K]

Answer:

$t=2.5\times 10^{-14}\ s$

Explanation:

We know that charge on electron

$q=1.6\times 10^{-19}\ C$

r= 2 nm

We know that force between two charge given

$F=K\dfrac{Q_1Q_2}{r^2}$

Now by putting the value

$F=9\times10^9\dfrac{1.6\times 10^{-19}\times 1.6\times 10^{-19}}{(2\times 10^{-9})^2}$

$F=5.67\times 10^{-11}\ N$

We know that mass of electron

The mass of electron

$m=9.1\times 10^{-31}\ kg$

F= m a

a= Acceleration of electron

a= F/m

$a=\dfrac{5.67\times 10^{-11}}{9.1\times 10^{-31}}\ m/s^2$

$a=6.2\times 10^{19} m/s^2$

$S=ut+\dfrac{1}{2}at^2$

initial velocity given that zero ,u=0

$20\times 10^{-9}=\dfrac{1}{2}\times 6.2\times 10^{19} t^2$

$t=\sqrt {\dfrac{40\times 10^{-9}}{6.2\times 10^{19}}}$

$t=2.5\times 10^{-14}\ s$

3 0

3 years ago

7. Describe about the difficultites that would arise due to lack of non-uniformity in measurement.

r-ruslan [8.4K]

Answer:

Many difficulties would arise if there was a lack of uniformity in the measurement of various weights and measures between business, industry, individuals and countries. The biggest implications for a lack of uniformity are in health and safety, equity and sustainability.

Explanation:

palike nlng po

6 0

3 years ago

Suppose you want to to double a copper wire's resistance. To what temperature, in degrees Celsius, must you raise it if it is or

sleet_krkn [62]

Answer:

T=280.41 °C

Explanation:

Given that

At T= 24°C Resistance =Ro

Lets take at temperature T resistance is 2Ro

We know that resistance R given as

R= Ro(1+αΔT)

R-Ro=Ro αΔT

For copper wire

α(coefficient of Resistance) = 3.9 x 10⁻³ /°C

Given that at temperature T

R= 2Ro

Now by putting the values

R-Ro=Ro αΔT

2Ro-Ro=Ro αΔT

1 = αΔT

1 = 3.9 x 10⁻³ x ΔT

ΔT = 256.41 °C

T- 24 = 256.41 °C

T=280.41 °C

So the final temperature is 280.41 °C.

8 0

3 years ago

Explain 5 things that could cause an incorrect mass when using the triple bean balance?

ludmilkaskok [199]

If the scale is not "zeroed". If you do not use grams (g) to lable your products. If you do not unlock the balance. [that's about all I got doll]

5 0

3 years ago

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