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3 years ago

10

How many cm are in 7 km?

2 answers:

kipiarov [429]3 years ago

7 0

Answer:

700000cm

Explanation:

1 km consists of 1000m and 1 m consists of 100 cm so 7×1000×100=700000cm

nikklg [1K]3 years ago

5 0

Answer:

70000 cm in 7km

Explanation:

There are 1000 m and 100 cm in 1 m in 1 km, so to find how many cm are in 7 km you need to do 10000 x 7. You get 70000

Have a nice day!

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Which of the following factors could you change in a system and not change its induced EMF?

krok68 [10]

The options attached to the question above are listed below:
A. Magnetic field.
B. Type of wire.
C. Velocity of the wire.
D. Length of the wire in the field.

ANSWER
The correct option is B.
The factors that determine the induced current in a system are: the number of wires in the coil, the strength of the magnetic field and speed of armature rotation [speed of cutting]. Generally, the induced electromotive force across a conductor is equal to the rate at which magnetic flux is cut by the conductor. The type of wire used does not affect the induced EMF.

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3 years ago

Read 2 more answers

If 20 grams of Zinc phosphate reacts with excess hydrochloric acid and produces 18 grams of Zinc chloride what is the percent yi

fenix001 [56]

Answer:

$Y=85\%$

Explanation:

Hello!

In this case, since we know the balanced chemical reaction, we are first able to realize there is a 1:3 mole ratio between zinc phosphate and zinc chloride; it means that we can first compute the moles of the desired product via stoichiometry:

$n_{ZnCl_2}=20gZn_3(PO_4)_2*\frac{1molZn_3(PO_4)_2}{386.11gZn_3(PO_4)_2}*\frac{3molZnCl_2}{1molZn_3(PO_4)_2}=0.16gZnCl_2$

Next, since those moles are associated with the theoretical yield of zinc chloride, we obtain the corresponding mass:

$m_{ZnCl_2}^{theoretical}=0.16molZnCl_2*\frac{136.29gZnCl_2}{1molZnCl_2} =21gZnCl_2$

Finally, we compute the percent yield by diving the actual yield (18 g) by the theoretical yield:

$Y=\frac{18g}{21g}*100\%\\\\Y=85\%$

Best regards!

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3 years ago

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denis-greek [22]

Answer:

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Explanation:

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3 years ago

It takes 495.0 kJ of energy to remove 1 mole of electron from an atom on the surface of sodium metal. How much energy does it ta

Zigmanuir [339]

Answer:

$\lambda=241.9\ nm$

Explanation:

The work function of the sodium= 495.0 kJ/mol

It means that

1 mole of electrons can be removed by applying of 495.0 kJ of energy.

Also,

1 mole = $6.023\times 10^{23}\ electrons$

So,

$6.023\times 10^{23}$ electrons can be removed by applying of 495.0 kJ of energy.

1 electron can be removed by applying of $\frac {495.0}{6.023\times 10^{23}}\ kJ$ of energy.

Energy required = $82.18\times 10^{-23}\ kJ$

Also,

1 kJ = 1000 J

So,

Energy required = $82.18\times 10^{-20}\ J$

Also, $E=\frac {h\times c}{\lambda}$

Where,

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

So,

$79.78\times 10^{-20}=\frac {6.626\times 10^{-34}\times 3\times 10^8}{\lambda}$

$\lambda=\frac{6.626\times 10^{-34}\times 3\times 10^8}{82.18\times 10^{-20}}$

$\lambda=\frac{10^{-26}\times \:19.878}{10^{-20}\times \:82.18}$

$\lambda=\frac{19.878}{10^6\times \:82.18}$

$\lambda=2.4188\times 10^{-7}\ m$

Also,

1 m = 10⁻⁹ nm

So,

$\lambda=241.9\ nm$

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3 years ago

Suppose you place a ball in the middle of a wagon, and then accelerate the wagon forward. Describe the motion of the ball relati

Alborosie

Answer:

It will have more speed/more acceleration than or the ground.

Explanation:

It will lean twords the side that moves and for ex if the wagon has a level to pull a gap down the ball will go forward

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2 years ago