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3 years ago

6

Which of the following would be an example of an uncontrolled experiment?A. The effect of water on different metals in a lab. B.

The effect of the jet streams on weather conditions. C.The effect of salt and water being mixed at different temperatures. D. The effect of heat on a plants growth.

1 answer:

Natali [406]3 years ago

5 0

Answer:

all of them can be uncontrolled but the one who is not controlled would be the effect of heat on a plant growth

Explanation:

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A typical wall outlet voltage is 120 volts in the United States. Personal MP3 players require much smaller voltages, typically 2

butalik [34]

Answer:

Number of turns in secondary will be 7

Explanation:

We have given primary voltage $V_p=120volt$

Number of turns in the primary is $N_p=3575$

Secondary voltage is given $V_s=235mV=0.235volt$

We have to find the number of turns in secondary

We know that $\frac{N_p}{N_s}=\frac{V_p}{V_s}$

So $\frac{3575}{N_s}=\frac{120}{0.235}$

$N_s=6.60$

As the number of turns can not be in decimal so number of turns will be 7

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4 years ago

5. Dry ice is an example of _________, which is the process of a solid turning directly into a gas. (1 point) precipitation melt

ki77a [65]

<span>5. Dry ice is an example of _________, which is the process of a solid turning directly into a gas. (1 point)

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4 years ago

A charge of 12 c passes through an electroplating apparatus in 2. 0 min. what is the average current?

Studentka2010 [4]

A charge of 12 c passes through an electroplating apparatus in 2.0 min, then the average current is 0.1 ampere.

<h3>What is an electric charge?</h3>

Charged material experiences a force when it is exposed to an electromagnetic field due to the physical property of electric charge. You can have a positive or negative electric charge.

Electric current is defined as the charge per unit of time.

The mathematical relation between current and the electric charge

I =Q/T

where I is the current flowing

Q is the total electric charge

T is the time period for which the current is flowing

As given in the problem A charge of 12 c passes through an electroplating apparatus in 2.0 min

Let us first convert the time period of minutes into seconds

1 min = 60 seconds

2 min = 2*60 seconds

=120 seconds

By using the above relation between electric current and electric charge

and by substituting the respective values of the charge and the time period

I =Q/T

I = 12c/120 seconds

I = 0.1 Ampere

Thus, the average current flowing through the apparatus would be 0.1 Ampere.

Learn more about an electric charge from here

brainly.com/question/8163163

#SPJ4

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2 years ago

Water heating over a stove

enot [183]

Answer:

Use a pot??

Explanation:

8 0

3 years ago

Read 2 more answers

Tungsten has a temperature coefficient of resistivity of 0.0045 (c°)-1. a tungsten wire is connected to a source of constant vol

Murljashka [212]

Answer:

$131.1^{\circ}C$

Explanation:

The power delivered in the wire is given by:

$P=\frac{V^2}{R}$

where V is the voltage of the battery and R is the resistance of the wire.

Since the voltage of the battery is constant, we can rewrite this equation as follows:

$V^2 = PR=const.$ (1)

At the beginning, the initial resistance is $R_0$ , and the power delivered is $P_0$ . Later, when the temperature increases, the power becomes $P_1 = \frac{2}{3}P_0$ , and the new resistance is $R_1$ . Using (1), we can write

$P_0 R_0 = \frac{2}{3}P_0 R_1\\R_1 = \frac{3}{2}\frac{P_0 R_0}{P_0}=\frac{3}{2}R_0$ (2)

So, the new resistance must be 3/2 of the initial resistance.

We know that the resistance increases linearly with the temperature, as

$R_1 = R_0 (1+\alpha \Delta T)$

where

$\alpha = 0.0045 ^{\circ}C^{-1}$ is the temperature coefficient

$\Delta T$ is the change in temperature

Using (2), we can rewrite this equation as

$\frac{3}{2}R_0 = R_0(1+ \alpha \Delta T)$

and we find:

$\frac{3}{2}=1+\alpha \Delta T\\\Delta T=\frac{\frac{3}{2}-1}{\alpha}=111.1 ^{\circ}$

So, the new temperature of the wire must be

$T_f = 21^{\circ}+111.1^{\circ}=132.1^{\circ}$

6 0

4 years ago