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3 years ago

The reason that the TLC chamber should be kept closed with a lid on it is Select one:

Physics

1 answer:

padilas [110]3 years ago

6 0

Answer:

d. to prevent evaporation of the solvent from the chamber.

Explanation:

TLC or thin layer chromatography is a technique which is used to separate the compounds on the basis of a principal that the different compounds have different solubility and adsorption to the two phases solid and liquid. It is also known as solid liqiud technique in which solid serves as a stationary base and liquid as a mobile phase. Solvent in the chamber should be ina small amount such that a little of bottom part of the plate below the spot should dipped in it. The lid of the chamber should be kept closed to avoid evapouration of solvent.

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Who invented physics?

Jet001 [13]

Answer:

I think Albert Einstein invented physics.

Explanation:

Iam soory if Iam wrong.

7 0

3 years ago

If R is the total resistance of three resistors, connected in parallel, with resistances R1, R2, R3, then 1 R = 1 R1 + 1 R2 + 1

rjkz [21]

Answer:

maximum error is 0.03333

Explanation:

given data

R1 = 100 Ω,

R2 = 25 Ω,

R3 = 10 Ω

1/ R = 1/ R1 + 1/ R2 + 1 /R3

possible error = 0.5%

to find out

maximum error

solution

we know

1/ R = 1/ R1 + 1/ R2 + 1 /R3

put all value R1, R2 and R3

1/ R = 1/ 100 + 1/ 25 + 1 /10

R = 20/3

now take derivative

dR/dR(i) = R²/R(i)² for i = 1, 2, 3

we have given error 0.005

so dR(i) = 0.005×R(i) for the i = 1,2,3

so the equation will be

dR = dR/dR(1) ×dR(1) +dR/dR(2) ×dR(2) + dR/dR(3) ×dR(3)

dR = R²/R²(1) ×dR(1) + R²/R²(2) ×dR(2) + R²/R²(3) ×dR(3)

put the value dR(1) and dR(2) and dR(3) and R

dR = (20/3)²/R²(1) ×0.005×R(1) + (20/3)²/R²(2) ×0.005×R(2) + (20/3)²/R²(3) ×0.005×R(3)

dR = (20/3)²/R(1) ×0.005 + (20/3)²/R(2) ×0.005 + (20/3)²/R(3) ×0.005

dR = (20/3)²/100 ×0.005 + (20/3)²/20 ×0.005 + (20/3)²/10 ×0.005

dR = (20/3)² ( 0.005/100 + 0.005/25 + 0.005/10)

dR = 0.033333

maximum error is 0.03333

8 0

3 years ago

You take a couple of capacitors and connect them in series, to which you observe a total capacitance

Zepler [3.9K]

Answer:

Approximately $\rm 5.7\; \mu F$ and approximately $29\; \rm \mu F$ .

Explanation:

Let $C_1$ and $C_2$ denote the capacitance of these two capacitors.

When these two capacitors are connected in parallel, the combined capacitance will be the sum of $C_1$ and $C_2$ . (Think about how connecting these two capacitors in parallel is like adding to the total area of the capacitor plates. That would allow a greater amount of charge to be stored.)

$C(\text{parallel}) = C_1 + C_2$ .

On the other hand, when these two capacitors are connected in series, the combined capacitance should satisfy:

$\displaystyle \frac{1}{C(\text{series})} = \frac{1}{C_1} + \frac{1}{C_2}$ .

(Consider how connecting these two capacitors in series is similar to increasing the distance between the capacitor plates. The strength of the electric field ( $V$ ) between these plates will become smaller. That translates to a smaller capacitance if the amount of charge stored $(Q)$ stays the same.)

The question states that:

$C(\text{parallel}) = 35\; \rm \mu F$ , and
$C(\text{series}) = 4.8\; \rm \mu F$ .

Let the capacitance of these two capacitors be $x\; \rm \mu F$ and $y\; \rm \mu F$ . The two equations will become:

$\displaystyle \left\lbrace \begin{aligned}& x + y = 35 \\ & \frac{1}{x} + \frac{1}{y} = \frac{1}{4.8}\end{aligned}\right.$ .

From the first equation:

$y = 35 - x$ .

Hence, the $y$ in the second equation here can be replaced with $(35 - x)$ . That equation would then become:

$\displaystyle \frac{1}{x} + \frac{1}{35 - x} = \frac{1}{4.8}$ .

Solve for $x$ :

$\displaystyle \frac{x + (35 - x)}{x \, (35 - x)} = \frac{1}{4.8}$ .

$x\, (35 - x) = 4.8$ .

$x^2 - 35 \, x + 168 = 0$ .

Solve this quadratic equation for $x$ :

$x \approx 5.7$ or $x \approx 29.3$ .

Substitute back into the equation $y = 35 - x$ for $y$ :

$x \approx 5.7$ and $y \approx 29.3$ , or
$x \approx 29.3$ and $x \approx 5.7$ .

In other words, these two capacitors have only one possible set of capacitances (even though the previous quadratic equation gave two distinct real roots.) The capacitances of the two capacitors would be approximately $5.7\; \rm \mu F$ and approximately $29\; \rm \mu F$ (both values are rounded to two significant digits.)

6 0

3 years ago

A student places two magnets as shown; with their south poles equal distances from a compass. The student observes that the comp

Gre4nikov [31]

Since the direction of the needle depends on the proximity of the magnet thus this test alone is insufficient to determine the stronger magnet.

<h3>What is a magnetic field?</h3>

A magnetic field refers to the region where the effect of a magnet is felt. The magnetic field can be observed by the use of a compass.

Now, we know that the closer the magnet is to the compass, the greater the deflection hence this test alone is insufficient to determine the stronger magnet.

Learn more about magnetic field:brainly.com/question/14848188

#SPJ1

6 0

2 years ago

a net force of 100 newton’s is a moving mass with an acceleration of 5 m/s. what is the mass of the object?

Jlenok [28]

F = ma

100 N= m . 5 ms⁻¹

100 / 5 = m

20 N ms = mass of object.

7 0

3 years ago